Thursday, August 31, 2006

P0300 code on 2002 Chevy truck 5.3L engine


Symptoms:

Rough idle with code P0300 (random misfire). When spark plugs were removed, the bank 2 plugs are covered with soot. Replaced plugs and wires and it ran briefly OK but misfired again after a few minutes.

Basic Concept:

If bank 2 is acting up, I would check the restriction first in bank 2 catalytic converter. If restricted, bank 2 will not be able to breathe causing the misfiring.

Repair Technique:

The exhaust backpressure can be checked by hooking a vacuum gage on the oxygen sensor port in bank 2. Pressure reading should not exceed 3 psi. If it does, the exhaust manifold can be dropped and see if misfiring stops. Be sure to reset the code after performing the repair.

Wednesday, August 30, 2006

P0118 and P1128 codes on 2000 Audi with 1.8L engine


Symptoms:

Hard starting after engine has warmed up including poor acceleration and rough idle. P0118 code (engine coolant temperature circuit defect) and P1128 (long term fuel trim system lean) were taken after scanning. Do I change the coolant sensor?

Basic Concept:

Whenever code P0118 appears and your thermostat is checked OK, replace the coolant sensor because it is a common problem on this model. What is happening is, the coolant sensor is stuck in flood mode causing the hard or long cranks because there is too much fuel. The other code is caused by a contaminated mass sensor that can be serviced or replaced.

Repair Strategy:

Replace the coolant sensor first to fix the first code and before servicing the mass sensor, make sure to check for vacuum leak using ATS tips or have it smoked by a garage. On some extreme case, the vacuum leak is caused by an intake manifold leak that requires a top end job. This is why you need it smoked if the 2nd code keeps coming back. When resetting the codes, remove the battery cables and touch them together for at least 15 seconds.

Tuesday, August 29, 2006

20002 Volkswagen Jetta with code P1128 and poor gas mileage


Problem:

Check engine light is on and when scanned, code P1128 came out which stands for lean upstream oxygen sensor. Gas mileage also got worst during this time. Do I change the oxygen sensor?

Basic Concept:

When this code shows up, check for vacuum leak in all vacuum hoses and top intake gasket. The oxygen sensor can be tested manually by feeding fuel or creating a vacuum leak. If the voltage reading of the sensor changes, it means the sensor is OK; otherwise replace the sensor.However, the most common fix for this code is to check and service the mass sensor. This will usually fix the problem.

Repair Technique:

Before doing anything, service the mass sensor first and reset the code. For details in servicing the mass sensor, contact ATS. If after road testing and the code still show up, then proceed in testing the vacuum leak and the oxygen sensor itself.
Details in testing the oxygen sensor is covered in ATS including the proper way to do a vacuum leak test.

Monday, August 28, 2006

2002 Caravan with codes P0442 and P0456 causing the check engine light to come on

Symptoms:

Steady check engine light in the dash panel after engine is started. Codes p0442 and P0456 coming on after being scanned. Checked and tightened up the gas filler cap and reset engine computer but the codes came back.

Basic Concept:

These codes pop up whenever there is a vacuum leak in the evaporative system comprised mainly of the vacuum (charcoal) canister and its solenoids, purge solenoids, vacuum hoses connected to it including the vacuum hose fuel tank connections, vapor separator and the gas cap. Normally, tightening the gas cap will do away with these codes but it seems there are other problem associated with it but the main culprit is the vacuum leak. Pay particular attention to the vacuum canister and its plastic connections that is proned to crack causing the vacuum leak.

Evaporative fuel system is a fuel emission recovey process use to channel fuel vapor from your fuel tank to your engine to get it burnt instead of emitting the fuel vapor to the atmosphere causing pollution.

Repair Strategy:

Do a visual inspection on all connections to the vacuum canister and the vacuum solenoids, vapor separator and all vapor hoses that can cracked over some time. ATS can provide you with the vacuum diagram of the system and if the vacuum leak cannot be found, it is highly recommended to have it "smoked" using a smoking machine that can detect even the smallest vacuum leak. The smoking machine is discussed in ATS or you can contact any garage to do it for you. Once the vacuum leak is found and repaired, reset the code and road test the vehicle to verify the code.

Sunday, August 27, 2006

Quick Tip for rough running engine with NO check engine light


Symptoms:

Very common on fuel injected engines that have a rough running engine but dissapears when rev up. When scanned for codes, none is found. This is prevalent especially if your engine has over 100 k miles.

Theory:

Over times, the top end of your engine accumulates carbon deposits on the following parts: cylinder valves, top of pistons and combustion chambers. This affects the combustion efficiency of the engine so that when on idle, the cylinder will fail to burn fuel completely resulting in uneven rpm. Solution? you can use a chemical additive fed in the intake chamber to dissolve the carbon and brings back better combustion and fuel economy.

Repair Technique:

A combustion chemical additive can be bought from any local store together with a vacuum fitting (see picture) so it can be fed to the engine intake at idle rpm. It will come with instruction so you can do it properly. And if you add a chemical additive for injector cleaning to your fuel tank plus a chemical spray cleaner on your throttle body then your chemical tune up is complete! (again read the chemical instruction so you can use the proper dosage and always make sure they are oxygen sensor compatible because if you are not careful, these chemicals can damage your oxygen sensor).

Saturday, August 26, 2006

1997-2000 Ford Truck AIR BAG removal tip: can you do it?




Problem:

If you have to change your steering gearbox connected below the steering column and the steering wheel has to come off, what safety precautions do you require?

Theory:

Before removing the steering wheel and the column, do these:
  • Remove the battery connections. Wait at less 1 minute before working on the air bag. This system can be activated even without the battery connected because of a back up system that can be activated within 1 minute of disconnecting the battery.
  • Disconnect the coil spring (located inside the steering wheel) yellow wire connector. This coil spring provides electrical connection to the airbag.
These 2 steps will prevent accidental application of the air bag module (see picture) so you can work on it.
For a detailed instruction on removing the air bag of your particular Ford Truck model, contact ATS.

Friday, August 25, 2006

2000 Honda Accord tip of the day: How to get the security code of your radio

Symptom:

Radio locked up and won't work. Usually happens when buying a used car and previous owner forgot to give the buyer the security code to enable the radio to work again.

Basic Concept:

On this Honda model, there is no common universal security code; instead the dealer will supply the particular code of the radio based on the serial number of the radio installed in the car.

Repair Strategy:

Using a mirror, get the radio serial number behind the glove box. The numbers are usually stamped on the bottom of radio housing. Once you have that, call the dealer and give them the number together with the VIN number of your car. On some cases, a trip to the dealer might be necessary so a proof of ownership of the car can be established. Once the code is available, reset the radio by touching the battery cables together 1-2 minutes. Then reconnect battery cables and turn radio on. A display of "CODE" will come out in the radio and the code you have can be fed to it using the radio preset buttons. For radio wiring diagrams and details of this procedure, contact ATS.

Thursday, August 24, 2006

2000 Ford Taurus fuel gage stuck in high level with P0460 code


Symptoms:

Code P0460 (fuel sending unit malfunction) is present despite changing the fuel-sending unit in the fuel tank. The fuel gage in the dash panel was also replaced but still the same result.

Basic Concept:

The only component that was not mentioned here in the fuel gage circuit is the flexible fuel sensor module. This part also control your fuel level indicator. This part has to be tested including the wires in between.

Repair Strategy:

Contact ATS to locate and test the flexible fuel sensor module and replace if necessary. Also check the wires for proper ground and continuity using ATS wiring diagram for this circuit supplied by ATS. Reset the code after performing all the repairs.

Wednesday, August 23, 2006

P0300 code on 2001 Chevrolet Venture with 3.4L engine


Symptoms:

Poor gas mileage together with rough idle rpm. When scanned showed random misfire P0300 code occurring after engine warmed up. Also has erratic acceleration, cutting out and sometimes stalling.

Basic Concept:

The easiest way to check this code is to verify the fuel system. The fuel regulator that sits on top of the engine can be disconnected by removing the vacuum hose connected to it. It can then be driven and observe if the symptoms will go away. Other test includes monitoring the fuel pressure while car is road tested to check performance of the fuel pump.

Repair Strategy:

To test the fuel regulator, hook up a fuel pressure tester at the fuel rail and record it. While idling, remove the vacuum hose during idle and fuel pressure should increase at least 10%. Also check for presence of gas in the vacuum hose that will indicate deterioration of the fuel regulator. On the same token, the fuel pump pressure can be tested and compared to specs by contacting ATS.

Tuesday, August 22, 2006

2001 Isuzu Rodeo with V6 engine with no start and no code



Symptoms:

Engine quit while cruising; timing belt is suspected broken. No codes were present when scanned with a scanner. Engine won't start ever since.

Basic Concept:

Timing belt should be replaced at regular intervals and if not, it can break while car is being driven which can cause further damages such as broken cylinder head valves or cylinder piston which will cause engine replacement.

Repair Strategy:

When this incident occurs, try removing the spark plugs and measure the engine compression. A zero reading or engine that would not turn is an indication of engine damage. The valve cover can be removed to verify further damage. If timing belt failed only and has not caused any mechanical damage, it can be replaced as shown in the picture. Procedures are available at ATS.

Monday, August 21, 2006

P0301 code on 1999 Surefire 2.4L engine with poor idle


Symptoms:

Cylinder 1 is misfiring as per code P0301 using a scanner. Idle is not steady and poor which sometimes stalls when on stoplights. Difficulty in starting is also observed in the morning when engine is cold.

Basic concept:

Misfiring code is easy to check when detected by a scanner. First and foremost, check compression of each cylinder and compare them to each other. On quad engines such as this, the ignition coils and injectors can be moved if compression is found to be normal. Once relocated, the code can be scanned again and see if the code move to another cylinder.

Repair Strategy:

If compression is normal and coils/injectors are relocated which results in a different code such P0302, P0303 or P0304, it shows the problem is either an ignition coil or injector problem. Remember to reset the code as soon as the coil or injector are relocated.

Sunday, August 20, 2006

P0300 code (random misfire) for 1995 Grand Am 2.4L engine


Symptoms:

Misfire code P0300 showed up in scanner accompanied by rough idle and lost of power. Spark plugs were checked and #3 is fuel fouled.

Basic Concept:

Aside from checking spark when top engine cover is removed (see picture), misfiring can be checked by measuring and comparing coil resistance and comparing them to each other.

Repair Strategy:

Before replacing any ignition parts, make a closer inspection of the coil boots and check for signs of crack. Contact ATS for TSB (service bulletin) regarding the engine oil pressure specs that can upset the valve openings of the cylinder head.

Saturday, August 19, 2006

1999 Volkswagen Beetle AC clutch not engaging: No code

Symptoms:

The compressor clutch won't engage. All fuses checked OK and if power and ground are directly fed to the clutch coil, it will work. There is no code from the ECM (engine computer).

Basic Concept:

The most common cause of this problem is the low/high pressure switch. Garages will normally drain the compressor content and fill it using the specified weight. If not available, try adding freon until the system is full.

Repair Strategy:

Using a wiring diagram, check the pressure switch for power supply. if present, replace the switch after making sure freon is at the right level. Also confirm that there is no ecm code like defective coolant sensor.

Friday, August 18, 2006

1999 Dodge Intrepid power door locks makes noise when locking/unlocking: no codes


Symptoms:

Both front door locks makes a high pitch noise when activating the lock/unlock buttons. There is no code when bcm (body control module) is scanned. Sometimes, the unlocking mechanism will not work but will work if you wait for a few minutes.

Basic Concept:

The door lock mechanism is a combination of a motor activated by a solenoid which pushes a linkage called "actuator". This linkage in turn makes the door lock moves to lock/unlock the door. This problem is very common on this type of vehicle.

Repair Strategy:

Open up your door panel and check the linkage. Most of the times, the actuators are worn and have to be replaced. An example on how it is done is shown in the left picture. Contact ATS for details to get the wiring diagrams so each component can be identified.

Thursday, August 17, 2006

99 Ford WindStar Door Ajar/Interior lights won't turn off


Symptoms:

Door ajar and interior lights always on even when all the doors are closed on this 1999 Ford Windstar. There is no check engine light coming in the dash.

Basic Concept:

Door latch switches are monitored by the vehicle's body computer called GEM. If one of them is stuck or defective, this problem will occur. Normally, a garage can use a scanner to monitor the GEM functions so that when you open the door, a code will appear to show the defective switch. In this vehicle, the check engine light computer is a separate system and does not control the body function such as the side doors and rear door openings.

Repair Strategies:

Since a generic scanner cannot be used to monitor GEM functions, try lubricating all the door latch switches with WD40 penetrating oil. Soaked them for about 10-20 minutes and try slamming the doors a few times to free up the switches. Usually, this method should fix the lights but if not, a garage scanner can be used to scan the GEM and replace the bad switch.

Tuesday, August 15, 2006

Today's tips for finding shorted wires

Let us say your power distribution box you has a circuit breaker that protect a few load example a power window circuit. This circuit could include the relays, switches, timers, controllers, motor and the wires in between. A simple way to check for shorts is to substitute 2 wires and plug it in to the circuit breaker. On the other end of the 2 wires, connect a small 12 volt socket with a bulb in it. When plugged in and there is a short, the bulb lights up, when short stops, the light goes out.

Once you have this set up, you can wiggle the wires, unplug each component of the circuit while watching the bulb and finding the short. You can even make the wires longer so you can see the bulb all the time.

Monday, August 14, 2006

97 Concorde with P0140 oxygen sensor (downstream) code


Symptoms:

97 Chrysler Concorde has P0140 code (oxygen sensor circuit no activity detected). Engine runs good but check engine light showing up. Gas consumption a little bit higher.

Basic Concept:

The rear oxygen sensor located after the catalytic converter (CAT) monitors the CAT performance. The sensor should oscillate between between 0.6 and 0.9 volt. If stuck or no movement, the oxygen sensor maybe dead or contaminated or shorted.

Repair Strategies:

Replace the oxygen sensor first and monitor the voltage reading again. In case it is still erratic or not within range, check the CAT or sensor wirings. To improve gas mileage, do a quick top end tune up as shown in the picture. Make sure the cleaner is oxygen sensor compatible. ATS will supply the sensor wirings if required.

Saturday, August 12, 2006

96 GM Astro has code P0101 and low fuel mileage


Symptoms:

This minivan set a code P0101 (Mass air flow A circuit range/performance) after driving in the highway for over 65 mph. The code was reset but returned after a week. During this time, the gas mileage also dropped.

Basic Concept:

This code deals primarily with the mass sensor and can be tested normally with a scanner like "All in One" scanner recommended in this blog. With engine running and scanner hooked up, the sensor readings can be monitored and analyzed for faults.

Repair Strategy:

Before buying the scanner, the map sensor and top of the engine can be viewed by removing the doghouse (see picture) to have a visual condition of the wirings and vacuum hoses to the map sensor.

Note:

To locate the wiring colors of the map sensor and location, please contact ATS if you are a member.

Friday, August 11, 2006

Parking and dash panel lights on ALL the time on 96 GM Astro: No codes


Symptoms:

Parking lights including license plate lights, dome and dash panel lights are on all the time even with the ignition off. There are no codes when scanned but this problem started after a trailer hitch package was installed.

Basic Concept:

After the installation of your trailer hitch package which includes the trailer harness wires, double check to make sure the connection to the terminals are correct. Sometimes, the wiring path is crossed causing a short creating a back feed that continuously supply power to these lights.

Repair Strategies:

Use a wiring diagram to verify the flow of power to the trailer harness. If necessary, unplug the fuses one at a time until the light goes out. the last fuse that was touched is the possible circuit. Also, the dash lights can be tested for power and ground supplies going to the headlight switch after dropping the steering wheel column cover (see picture shown on the left).

Note:

To get the appropiate wiring diagram for the lights, please contact ATS.

Thursday, August 10, 2006

Has "check engine light" on but vehicle runs OK!


Symptoms:

Vehicle runs OK but check engine light comes on after driving a few minutes. Sometimes the light will go out but lately, it will remain on all the time.

Suggestions?

Basic Concept:

Whenever there is an internal failure in your electronic system like sensors, solenoids, injectors, computer,etc... the event is stored in your computer and is shown by the check engine light. (See the picture as shown on the left. (In this instance, the ignition key is on but engine is off causing the battery and engine oil light to come on also).

Repair Strategies:

Try resetting your computer first by disconnecting the battery negative terminal or disconnect the "ecm" fuse in the fuse panel for a few seconds. For newer model cars and trucks, check with your dealer if it safe to disconnect the battery or contact ATS. If you have a serious code, it will come on again and all you do is scan the computer to determine the code number.Once you have the codes, contact ATS and we will email you the fix.

TIP:

Most check engine light with no performance problem comes from loose fuel tank cap. Try tightening that first and reset the code. If code comes back, contact ATS.

Wednesday, August 09, 2006

Engine overheating: Coolant boiling but no codes!


Symptoms:

Especially true in summer time where hot weather is common. Engines start to boil which can be monitored in the dash panel gage. Will continue even when thermostat is changed. Overheating usually occur after a few minutes of driving inside the city but stop when driven in the highway. No engine check code when scanned. What is causing this?

Basic Concept:

One of the most overlooked components in your cooling system is your radiator. Any build up of rust inside your engine gathers in the radiator. This is especially Engine overheating: Coolant boiling but no codestrue on vehicles which are 5 years old or older. When the rad flow is restricted, overheating can occur in a lot of stop and go driving especially in the city. During highway driving, there is more coolant flow resulting in lower coolant temperature. Recommendation? Flush your cooling system at least once a year before summer.

Repair strategies:

Anybody can buy a "flushing kit" from your local parts store. If can be connected to your coolant hose and house water supply to push out the dirty coolant from the rad. The kit is cheap and comes with instructions so you can do it easily. Make sure to replace the coolant with a 50-50 mix of coolant and water after you are done.

Note:

Contact ATS in case the overheating persists.

Tuesday, August 08, 2006

1994 Grand Prix: wires shorted but no codes!


Symptoms:

Car fuel pump was changed 2 weeks ago but won't start. Every time the starter switch is turned on, the fuse at the electrical center #2 inside the hood blows. The fuel pump circuit does not seem related to this job. There is no check engine light code when scanned. What to do?

Basic Concept:

A good way to trace a shorted wiring is thru the use of a WIRING DIAGRAM. Looking at it, there seems to be no connection between this problem and the fuel pump. If it is, it should have acted up as soon as the fuel pump was installed.

Repair Strategies:

Using a wiring diagram, connect a jumper wire hooked up to a circuit breaker to allow the circuit to work continuosly. When the amperage goes high and trip the breaker, it will just reset itself. You can also use a needle counter gage to monitor the location of the short. Once this system is set up, you can start disconnecting the circuit loads:

theft deterrent relay
trany range sensor
starter assembly

Disconnect these loads one at a time until the breaker stops tripping. The last load you touched is the location of the shorted circuit.

Note:

The needle counter gage has a needle that oscillates in the direction of the short. For more details, check ATS.

Monday, August 07, 2006

1999 Honda CRV with code P0172 and has poor mileage


Symptoms:

This vehicle has an intermittent stalling and has poor gas mileage. When scanned for codes, P0172 (fuel system rich) is found stored in memory. Fuel regulator and oxygen sensors checked OK and all injectors were also replaced including a complete tune up. However, after doing all of these, the code still came up?


Basic Concept:

One of the basic test that was not included here is the vacuum reading. This is important because it will save a lot of unnecessary parts if this was done first. On this model, expect a reading of 20 inch or higher. If you get lower than this, check the timing belt.

Repair Strategies:

Get the engine to idle on park and hooked up a vacuum gage to one of the vacuum hoses in the intake manifold. If reading is lower than the one indicated above, replace your timing belt especially if it has over 90,000 miles on it. Reset the code after replacement before taking it for a road test to make sure the code is gone.

Note:

For 1999 or newer Honda, use 90,000 miles timing belt replacement interval, for 1998 or older models, use 60,000 miles. For details on how to replace the timing belt, please contact ATS.

Sunday, August 06, 2006

P0171 lean condition obd2 code on 1996 Mazda 626 engines


Symptoms:

This code P0171 keeps coming up even after resetting the code. Other symptom includes intermittent hesitation, surging when shifting in gears. Oxygen sensors (both upstream and downstream) show good reading.

Basic Concept:

This early OBD2 system is popular for mass sensor failure. It is attributed to the loose mass sensor mounting screws that get loose and would later allow unfiltered air to contaminate the wire elements of the mass sensor.

Repair Strategies:

When encountering this code, check first the mass sensor and its mounting screws. If loose, take the mass sensor out and clean the wire elements of the sensor with brake spray cleaner. When installing, use a locktite to secure the screws to prevent it from getting loose.

Note:

To get the exact wirings of the mass sensor wires including its color,please contact ATS.

Saturday, August 05, 2006

Beware: Buying vehicles with Scanner no Airbag Communication


Symptom:

Before paying for a used vehicle, buyers usually take it to a garage for inspection. In this case, the Airbag won't communicate with the scanner when testing for codes. There is no apparent Airbag problem and the ABS light works normally when ignition key is turned on. However, the mechanic inspector has to fail the inspection. Why?

Basic Concept:

When a vehicle is involved in a collision, the airbag is usually deployed and they are sometimes expensive to re-install. To get around this, some garage or private individuals who has some knowledge of electronics, will NOT re-install the airbag and manipulate the Airbag indicator light. When the engine is started, the airbag light usually comes on for a few seconds and come off after the engine runs. If there is a missing airbag, of course the light will be on all the time. This can be manipulated by using capacitors to shut off the light. It then looks normal and if the vehicle is sold really cheap, a buyer will do away with inspection.

Repair:

mechanics usually spot this kind of problem when there is no communication with the scanner. Sometimes, by just looking at the new paint or bumper repair. As in this case for a 2001 Sonata (shown in the picture), the bumper looks like it was just replaced. If the scanner has no communication, a complete wiring checks should be done to determine if the airbag is present or not. Sometimes, while replacing the bumper, a wire could have been misplaced or loosely connected causing no communication also.

Note:

To get details for the airbag wiring diagram, please contact ATS.

Friday, August 04, 2006

89 GM truck with check engine light but scanner won't communicate


Symptoms:

This GM truck was brought to a mechanic friend's shop from out of town (yesterday...here in Calgary) and when it runs, the check engine light stays on and flickered.The idle is also a bit erratic or rough. The mechanic changed the ecm (computer) but it has no effect. We then cut the SES light wire terminal at the ecm but the check engine light bulb remained on. We suspect, the bulb is getting a back feed due to a shorted wire or connection.

Basic Strategy:

As soon as you start this vehicle, the check engine light should come on a few seconds.After starting, the light should go away unless there is faulty (shown by codes) sensors or components in the electrical system.

Recommended fix:

Access the ecm wire terminals and check the readings of all ground connections. Any ground reading higher than 0.250 volt is a suspect circuit. Check also the reference voltage which is usually 5 volts. If reading is different from this, undo all the load connections like IAC motor, injectors, alternator or other solenoid until the reference voltage returns to normal. The last one you touched is the culprit load circuit.

Note:

Looking at the engine compartment (see picture), I would change the complete wiring harness first. It is too costly to do the tests (above) which can still re-occur in other circuits.Also,is the customer willing to pay for ALL the wiring tests? A complete wiring harness is usually available from most salvage yards.

For proper ecm test and wiring diagram, please contact ATS.

Wednesday, August 02, 2006

96 Honda Accord Power door lock acting funny, no codes


Symptoms:

Automatic door lock mechanism is erratic causing it to go up and down while car is cruising. This takes a few minutes and will finally stop on it own.

Basic concept:

The door lock automatic is activated by door lock actuator which connects to your linkage that opens and closes the door lock. Combined with a solenoid, it moves a plunger to activate the linkage.

Repair:

Most common fix for this is to open the door cover panel to access the door actuator. Then check for presence of good supply of power and ground. If both are present, replace the door actuator.

Note:

To locate the wire colors of the door actuator, please contact ATS.

GM trucks with vortec engines (96-98) fuel problem but no codes.


Symptoms:

Hesitation, cutting out, stalling at stop signs and later no start

Basic Concept:

Vortec engine uses a centralized fuel system which is very sensitive
to fuel pressure settings. Sometimes, even if the pressure is lower than
1 psi (usually rated at 60-66 psi), it will start acting up.

Strategy for fixing:

If you are having the above symptoms, try first getting the code to see if
the electrical system is OK. On this engine, testing the fuel with carb spray
will not work and noid light tester cannot be used. The only check to do after
verifying the code is to check the fuel pressure as shown above. If your reading
is not within specs, replace the fuel pump inside the fuel tank.

Note:

Vortec engines are used commonly on all GM trucks with 4.3 L and 5.7L engines but
check with ATS first to confirm.