engine codes 26 and 31 on 1993 grand am, V6

[tubbydad]

can anyone tell me what a "quad driver module circuit" is?

also, what is the "park/neutral position switch circuit"?

what kind of problems do i need to look for with these 2 codes?, any help would be greatly appreciated

[3100]

quad driver circuit I think has to do something with injector firing

park/neutral safety switch is safety device that prevents you from starting your car in gears other than park or neutral

sorry code 26 is for Evap or Egr solenoid circuits


Quad-Driver Module (QDM) #1 circuit
applies to:
- AIR pump relay circuit
- EGR solenoid
- EVAP solenoid

[xeroinfinity]

Just because you have a Quad driver code doesn’t mean the Quad driver is bad. All a Quad driver code means is that an expected value is not present when its suppose to be. Also a Quad driver is a techy name for 4 on-off switches arranged in a group, hence the name Quad driver.

The ECM watches the voltage values on each switch and knows that if the switch is on, a voltage value will be seen. When the switch is off the opposite voltage value will be seen.
What can set a quad driver code? You’d be surprised. How about a bad bulb? How about a bad fuse?
Start with checking your fuses. There can be up to 3 fuses that supply power to circuits controlled by the Quad drivers.

- If the fuses are good, check the, Up shift light bulb, coolant hot bulb, shift to drive bulb, A/C relay, coolant fan relay, EGR solenoid, Canister Purge solenoid, even a speedometer output signal goes to one of the switches on the Quad driver.
Its likely that the Quad driver code is present because the computer is not seeing the information that it expects to see at one of the switches.

It is possible that your Park Neutral Saftey switch is faulty or the wires have a short causing the Quad driver code.

Good Hunting

ps: codes 26 & 31
26 Quad-driver sense voltage shows a low voltage when battery voltage should be present or if the sense voltage shows battery voltage when a low voltage should be present.

31 Park/Neutral switch was open for 4 consecutive starts, or Park/Neutral switch was grounded with transmission in high gear and vehicle speed was above 45 MPH for 12 seconds.

[tubbydad]

where is the cooling fan relay?, i think it may be the cause, because i dont think the fan is coming on. i know the fan itself works, because it was straight wired to the fusebox when i got the car. unhooked it after i put a thermostat in it

[xeroinfinity]

Cooling fan relay should be along the fire wall, furthest to the pass side. Though these can get mixed around. This could be why the Quad code was given.

[tubbydad]

ok, the fan IS kicking on, what are the chances of the safety neutrl switch causing both of the engine codes coming up. the car only starts in park, not even in neutral. please let me know, i aprreciate it

[xeroinfinity]

I would check the PNS switch, could jsut be the wiring.

I cant remember if these switches are adjustable either....
Do your back up lights work ???

Edit

I also found some more specific trouble codes.
26 QDM Error Shorted Throttle Switch Circuit (DFI)
Might check/test your TPS.

[tubbydad]

yeah, the reverse lights work. ill check the TPS tomorrow morning.

one more prob, can you think of any reason my fog lights dont work, now that i have changed the dash harness last week?

[tubbydad]

i think whatever is throwing my engine code 26 has something to do with the tacometer, when idle the light goes off, but when i start to drive, and get around 45 mph, my tach reads around 1200, anything higher than that pops the code, what controls the tach, because ive put 3 diff throttle position sensors in it, and still doing the same. your help would be appreciated

[xeroinfinity]

Didd you inspect and test the wiring to/from the TPS to the ECM ??

[tubbydad]

how do i go about doing all that?, are you saying i may need to change the hood wiring harness too?

[tubbydad]

i got to thinking about it, when i got the car, it had no thermostat. i did not know this until about 2 months later, up until i put the thermostat in, the engine light did not come on. i put it in, and then the light started coming on. any ideas?????

[xeroinfinity]

Well that would lead me to believe that either your temp sending unit wires have a short and or your temp sensor is bad.

Which with the quad codes Id lean toward the wires having a short somewhere.

[tubbydad]

ive checked the wires, fixed 2 of them. if the temp sender was bad, would the temp needle go up, because it does. i have noticed that it only sends the code when it has had time to warm up. like if i get in, crank it up, and go, the engine light wont come on until the engine heats up some, im baffled and confused with this one. if by chance its the TCC circuit, how do i check and or fix that?

[tubbydad]

also, when im driving, if i hit the break for a few seconds, the engine light will go off, then when i accelerate again, the light will come back on. ive got it down to just engine code 26.

also, how do i go about checking whats wrong with my ABS, the ABS light stays on all the time, whether its idling, or doing 90, any suggestions?