check engine

[parkav]

the check engine light at the dashbord sometimes going on and of. ignition coils and ICM are new.
what can it be.
EGR-valve or O2-sensor?

 

[HotZ28]

You need an OBDI/OBDII capable scanner to see what the codes are! Otherwise, you are replacing parts that may not be defective and a waste of money! Have you replaced the EGR?

 

[BuickGirlFromMars]

its likely an emissions equipment working part of the time like a camshaft position sensor or idle air control... maybe... coolant sensor.. etc. without more info we cant help. any symptoms

 

[techmann]

The most common thing that makes the light come on is a fuel code. Make sure you don't fuel the vehicle while the engine is running. The engine MUST be off while fueling. After fueling the vehicle, make sure you spin the cap a few full turns to secure it. IF this is the problem, the light should go out in a day or two, or have someone clear the code.

 

[Drakito]

Without you scanning the check engine light we can guess all day and be completely wrong, every time. We need actual data from a scan tool, then we can point you in the correct direction.
That's because there are more than 600 different out of spec sensor readings in multiple circuits that can cause it to come on, then off.

 

[BuickGirlFromMars]

Without you scanning the check engine light we can guess all day and be completely wrong, every time. We need actual data from a scan tool, then we can point you in the correct direction.
That's because there are more than 600 different out of spec sensor readings in multiple circuits that can cause it to come on, then off.

not to mention self-faults, intermittent signals, values that take too long, eratic behavior, codes for to-be-had issues, body and chassis codes which are important(ABS, TCS, airbag lights some codes will also set the DTC light), misfires, checks,

 

[HotZ28]

I have never seen yet where an ABS, TCS, SAR would set an CEL emission code. Maybe that could happen if the PCM & BCM ABS all failed? Never I have seen those three events happen simultaneous either!

 

[BuickGirlFromMars]

I have never seen yet where an ABS, TCS, SAR would set an CEL emission code. Maybe that could happen if the PCM & BCM ABS all failed? Never I have seen those three events happen simultaneous either!

i was watching videos on buick tech stuff from the 90s and it said certain severity body and chassis codes would set DTC but usually only if that meant impaired modules could mean actively dangerous or performance affecting things. like ABS that cant reliably operate but before it could "know" to turn itself off and stay off. or huge suspension wear if related. or if a multi-system code set. car-to-car basis, year im sure too

97-99 i believe literature wrote abs + tcs light and active stability sit. would set

 

[parkav]

yesterday the check engine lamps flash on.
i keep the engine running, because if i turn it off the engine-light is going off.
i connect my actron 9690 scanner with the car, and get the failure code P 0705.
i delete it, and since this time no check engine light.
whats about that?

 

[HotZ28]

yesterday the check engine lamps flash on.
i keep the engine running, because if i turn it off the engine-light is going off.
i connect my actron 9690 scanner with the car, and get the failure code P 0705.
i delete it, and since this time no check engine light.
whats about that?

Code P0705 Buick: Transmission Range Sensor Circuit Malfunction

The Transaxle on this vehicle has a Park Neutral Position (PNP) and Back-up switch. This switch incorporates a transaxle range selector switch. There are

www.autocodes.com

 

[Drakito]

You deleting the code clears it from the memory of the ECM. It will not come back unless the situation that caused the code to come on in the first place happens again.
The transmission selector switch on your generation of car I believe is bolted to the top of the transmission below the selector cable.

 

[parkav]

can it be......the code P0705 Comes up, if i check the OBD System with running engine?
yesterday i scan the System without flashing check engine-bulp, the code is still there. if i turn the engine of, the codes doesnt exist.
but i can not scan the System without running engine, everytime when i turn it of, the failure code is gone.

 

[BuickGirlFromMars]

Sounds like a ecm problem if that is the case, it should be stored historically which can be seen as a code still even if not active.

 

[BuickGirlFromMars]

A 95 Park avenue might not have Self check in its diagnostic ability or your scan tool cannot read the OBD 1.5 protocol

 

[parkav]

now i have renew the neutral-safety switch sensor/range sensor and the failure code P 0705 is gone.
if the check engine light comes again i will see, and report.

 

[parkav]

the check engine light comes again, now with the failure code P0640, somebody have an idea?

 

[Drakito]

In 95, that code can be multiple things. It can be the Quad driver module circuit 1 fault, MAF sensor out of range, or Crank sensor out of range. 95 is not full OBD and did not have everything standardized quite yet. That would be 96 model years.
But for more 95's I could find it is the QDM. Here is a troubleshoot guide with flowchart for diagnotstics.

Code P0640 for 1995 SC

I'm trying to help a friend with a 95 SC and has a code P0640. It is a quad driver circuit but don't know which 4 circuits are involved for troulbleshooting. Un

rivperformance.editboard.com

 

[parkav]

now i have renew the MAF Sensor.
if i drive the car the check engine light is coming on and of however it like, but without any readable failure code.

 

[BuickGirlFromMars]

A flashing light should mean misfire and you should not be driving. You replaced the MAF sensor you say? You shouldnt throw parts at a car from a code, especially obd1 or obd 1.5 . Your code means the computer is receiving signals from the MAF(Or lack thereof) that are not in its specified value range. AKA, its reading that you are receiving less than 0 air or its receiving more air than possible at a given temp, air presssure, speed, rpm, etc.

 

[parkav]

the light dont flash, it shines.
it shines without system if i drive the car, and if i turn it off it goes out.
if i start the engine once again and drive the lamp is off, but comes sometime.