OBD II code retrieval and decoding

[Irish_Alley]

whats it doing?

[VileZambonie]

Right, is there a drivability issue or just the EGR code coming up?

[gunrac]

whats it doing?

Really is not acting up in anyway, just the idea that the _Check lite only comes on after good running temp. is reached._ Code 32, is what it shows when jumping A+B on the pinout as I understand it. Not sure if I got a bad EGR. It did pass the vac test before installing. Vacuum line is good. The ECM along w/IAC are also new.  The truck runs real good, no issues at all.
This is my reason for concern:
I'm still not sure what caused the bent valve issue. I'm leaning toward the old EGR being bad w/the manifold being plugged pretty tight w/carbon. Most of that was on right side, but #7 intake valve give up. The plugs showed the engine was running very lean.

I just did get a 100 mi. on it since the valve job. Don't believe it has enough run time to really show anything by checking plugs, but I'll pull a couple today.

[VileZambonie]

Circuit Description:
 The ECM operates a solenoid to control the Exhaust Gas Recirculation (EGR) valve. This solenoid is normally closed. By providing a ground path, the ECM energizes the solenoid which then allows vacuum to pass to the EGR valve.

DTC 32 Will Set When: The ECM monitors EGR effectiveness by de-energizing the EGR control solenoid; thereby, shutting "OFF" vacuum to the EGR valve diaphragm. With the EGR valve closed, and O2S fluctuating normally, short term fuel trim counts will be greater than they were during normal EGR operation. If the change is not within the calibrated window, a DTC 32 will be set.

 The ECM will check EGR operation when:


•Vehicle speed is above 45 mph.
•Engine vacuum is between 15 and 60 kPa.
•Throttle angle between 6 and 30%.
•No change in throttle position while test is being run, max 4%.
•EGR on threshold 98%.

Action Taken (ECM will default to): The Malfunction Indicator Lamp (MIL) will illuminate.

DTC 32 Will Clear When: Conditions for fault are no longer present and Tech 1 "Clear DTCs" function is used or 50 ignition switch keycycles have passed with no further faults or ignition switch is turned "OFF" and ECM B fuse is removed for 10 seconds.

DTC Chart Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.


1.By grounding the diagnostic terminal, the EGR solenoid should be energized and allow vacuum to be applied to the EGR valve, and the vacuum should hold.
2.The MIL should also flash while the diagnostic terminal is grounded. If the tight does not flash, this may indicate that the "quad-driver" has been damaged by low resistance in TCC circuit.
3.When the diagnostic terminal is ungrounded, the vacuum to the EGR valve should bleed off through a vent in the solenoid and the valve should close. The gage may or may not bleed off but this does not indicate a problem.
4.This test will determine if the electrical control part of the system is at fault, or if the connector or solenoid is at fault.
5.This system uses a negative backpressure valve which should hold vacuum with engine "OFF."
6.When engine is started, exhaust backpressure should cause vacuum to bleed off and valve should fully close.

[hatzie]

Dang lite came on......code 32 again.......I don't know? Pic of my feed.....what do I have.....+ help on the code.....

Your center key is on the bottom and the side keys are on top.  Is this picture downside up?

callin my a to b......right top to left

Nope unless your picture was downside up...
Bottom Left.  Note the Connector locator key positions....
You have A,B,C,G,H,J,M populated.  8192 baud ALDL.  The 1994 ECM should spit out quite a lot of info over the ALDL serial link.


[A] ECM Ground
[B) Diagnostic Enable
[C] ECM to Air Switch Solenoid
[G] Fuel Pump Prime
[H] RWAL VSS
[J] ??
[M] 8192 Baud TTL serial data TX & RX

[gunrac]

Thx guy's. That is a lot of heavy knowledge, and I appreciate it. I have reread it  several times. Now, if I can only get my weak mind to comprehend it all.

[roundhouse]

Good info here


Sent from my iPhone using Tapatalk

[gunrac]

 W/the help of Jim_Hensley, we went thru the process of elimination, our test pointed to the EGR valve itself.  Ended up replacing the new EGR valve, with another new EGR valve.  Go figure.. Reset the ECM.  made a couple 10 mi. runs. No check lite.