Its an Actron 9185.

thanks,

Drew

Regarding the IAC, I replaced it with a new unit I had on the shelf with no change. With the IAC off and engine running, I can stick my finger where the pintle goes in the TB and cause the engine rpm to drop significantly. Didn't try to stall it like that but I imagine I could. I can try tomorrow and see if it will die.

thanks,

Drew

I removed the IAC this morning and, with it still plugged in, when you KOEO nothing moves. Is this expected?

I measured how far the pintle sticks out from the mating surface of the sensor (~1") and then made same measurement on throttle body. IAC is definitely closed. Funny thing though, when I did KOEO to see if IAC would move, the fuel pump decided to keep running and running instead of just priming the system. I know the ECU grounds the pump so that boggles my mind. I keyed off and back on again and it primed like normal. I really think the ECU is shot.

Can someone please provide info about the quad drivers? I need to know which sensors are controlled by each quad and also if someone has some wiring diagrams that would be very much appreciated.

thanks,

Drew

I'm thinking the ECM/PCM may be the culprit. This series of GM modules had many different anomalies. Try this first. Unplug the MAF and try to start. See if it coded. Do the same thing for other sensors ie. TPS, IAC etc. If the ECM/PCM does not code the module is likely bad. Tonight I'll look over the wiring diagrams and see if there'* a common connection between the FP and the drivers (other than the module).

Here'* the info for your P1640 quad code. You'll want to read it over and get a good handle on the system(*) and how they work and then formulate your approach to diagnosing the problem. The flow charts are not always the best way to troubleshoot. These flow charts have been aptly called 'trouble trees' by mechanics because of the many times following them will lead us to replace perfectly good components.
For quad faults you want to check the resistance of the devises being monitored, ie. for a solenoid you will measure the resistance of the solenoid and make sure it'* within specs. If the devices are OK you'll want to test the wiring from the module to the different devises. If the devises are OK and your wiring is OK and yet it codes the module is the likely problem.

You can test the purge solenoid and TCC solenoid circuits. The boost is for TC engines which you don't use.

Before you start tearing into this take a look at the cooling fan fuse. It'* a 10 amp fuse and it supplies voltage to several of the quad driver devises. That fuse may be blown.

OK will do. As a side note, both fans come on when I turn the AC on.

thanks for the help.

Drew

OOOOOK,

So with the car running, if I unplug the MAF the car dies. If I leave it unplugged the car will start but it idles low and does the chug chug chug thing trying to stay alive. Yes, it threw a MAF and Lean O2 code in addition to the same Quad driver stuff. Since the RPM was actually below 2K, I tried listening around and spraying brakekleen (not the best choice I know) to see if I could get a response in rpm. Nada.

I measured the resistance of the EVAP and gto 65ohms. 12V to pink wire with KOEO

I measured the resistance of the TCC between brown and pink and it was 37ohms. Very tricky one to measure. Also getting 12V to brown wire with KOEO

Checked ALL of the interior fuses and they are all good. Both the fuses by the PCM and those in the driver'* foot well.

Regarding those pics you posted, is that ALL the sensors for QUAD 1?

As a side note, my scanner has option for field service mode. Trying to figure out what that is.....

thanks for the help,

Drew

whoops, meant brown and tan/black for the TCC. How the heck can you edit a post on here?

Drew

Field Service was a way to get serial data through the CEL but it'* also a quick function of the scan tool.
Without a scan tool.......If the diagnostic terminal is grounded with the engine RUNNING, the system will enter field service mode. In this mode the MIL will display whether the engine control system is running in Open Loop or Closed Loop. When running in Closed Loop, the MIL will also display whether the engine is running lean or rich.
In Open Loop operation (during engine and oxygen sensor warm up) the MIL light will flash 2.5 times per second. Once the oxygen sensor is fully warmed and the control module decides that its feedback is reliable, the system will enter Closed Loop operation and the MIL will flash 1 time per second. During Closed Loop operation, if the MIL remains OFF most of the time, then the engine is running lean. If the MIL remains ON most of the time, the engine is running rich. In open loop operation the MIL light will flash 2.5 times per second.

I don't know why they don't allow for edit/delete. They should.....