12200411 PCM swap for 1996 to 2000 GMT400 trucks

[Spareparts]

Just tried unplugging it. Makes no difference starting or trying it both ways running.

 

[1998_K1500_Sub]

Did you fix the EGR wiring? The 0411 controls the EGR valve in a different manner and a new 12V supply wire has to be run back to the PCM from the valve to the corresponding pin on the PCM. If not the valve will hang fully open. Easy way to check to see if it is the problem is to merely unplug the valve.

Lextech should include this in the spreadsheet(s). Maybe he did, it would manifest in the wiring connections - pin swap instructions.

Suggestion to override any EGR wiring issue: Disconnect the EGR's plug, and disable the EGR in the tune (need to do both AFAIK, the first to disable the valve and second to disable the ECU from even thinking about using the valve).

Yet another "Oh yeah, and then there's this..." nit regarding the 0411 swap, but we're learning...

 

[1998_K1500_Sub]

From this description (attached, 1998 GM Service Manual), it appears like the EGR works like this, using a five (5) terminal connector:

- Power (+12) is applied on Terminal E

- PWM signal from the ECU is applied on Terminal A, effectively providing a path to ground, through the solenoid, for Terminal E; this energizes the solenoid in proportion to the PWM signal's duty cycle and moves the pintle

Feedback to the ECU comes from a pintle position sensor, as follows:

- Sensor GND is Terminal B, connects to GND reference on ECU

- Sensor +5 is applied from ECU on Terminal D

- Senor output to ECU is on Terminal C

Perhaps the 0411 has slightly different wiring.

 

[L31MaxExpress]

From this description (attached, GM Service Manual), it appears like the EGR works like this, using a five (5) terminal connector:

- Power (+12) is applied on Terminal E from IGN to power the pintle's solenoid ("motor"); however, the solenoid doesn't just cause motion by itself; rather, it in combination with the PWM signal applied by the ECU causes the pintle to move. Without +12, the solenoid ("motor") won't operate and the pintle will remain at rest.

- PWM signal from the ECU is applied on Terminal A; the duty cycle of this signal determines the position of the pintle, and changing the duty cycle changes the pintle's position... provided +12V power is applied to Terminal E as well.

- GND for the solenoid ("motor") is through the EGR valve's case it appears

Feedback to the ECU comes from a pintle position sensor, as follows:

- Sensor GND is Terminal B (wired to the ECU's GND reference)

- Sensor +5 is on Terminal D (this likely is supplied by the ECU)

- Senor output is on Terminal C (this is the signal back to the ECU which indicates the position of the pintle).

The problem is more with the 0411, the valves 12 volt source is the 0411. I believe the PWM signal is oddly controlled by the PCM on the positive side. If the valves 12 volt source is not connected to the PCM, it opens wide open. Unplugging it keeps the valve closed, which is why I suggested it as a diagnostic test.

He did say it was not his issue though.

 

[1998_K1500_Sub]

the valves 12 volt source is the 0411.

The GM Service manual seems to say something different. It specifically mentions "Ignition" as the +12V source. Perhaps that's particular to that era's ECU.

 

[L31MaxExpress]

The GM Service manual seems to say something different. It specifically mentions "Ignition" as the +12V source, but perhaps that's an artifact. It also makes a confusing statement about the solenoid current passing through the ECU.



Without +12V power, and based on the GM Service manual description, I can't see how the pintle would open.

Just going by what I've read. My Suburban's sitting outside, I could go experiment...

Throw the 98 service manual out of the window with an 0411.

The EGR valve will stay closed unless exhaust backpressure blows it open. Pull the valve out. The pintle is rather easy to move with your finger. I have seen a Bank 1 cat that started plugging up force the EGR valve wide open. I have also seen the egr pintle spring become weak or break and the EGR valve partially opens at idle or off-idle or opens much more quickly than the PCM is commanding.

Below is the EGR wiring diagram using an 0411. The EGR is controlled on the positive side with an 0411 and the negative side on an older black box. If you do not run the positive wire to the correct pin on the 0411, the EGR recieves a constant 12 volts and the valve fully opens.

You must be registered for see images attach

 

[L31MaxExpress]

My buddy and his friend did the wiring on his 0411 swap ignoring the EGR step. Acted exactly how this guys truck does.

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[Supercharged111]

My buddy and his friend did the wiring on his 0411 swap ignoring the EGR step. Acted exactly how this guys truck does.

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Same with my dually, ignored the EGR stuff and it ran like ass. Unplugged it and it was a new beast. I missed it on the 1500 too but never realized it because that has it physically deleted.

 

[Spareparts]

Mine runs fine once it starts. I think the problem is whatever tells it to richen up for start up is not working ,either mechanical or the tune I don't know..
Some say to disable the egr and some run it.
What effect does it have disabled?

 

[1998_K1500_Sub]

Throw the 98 service manual out of the window with an 0411.

The EGR valve will stay closed unless exhaust backpressure blows it open. Pull the valve out. The pintle is rather easy to move with your finger. I have seen a Bank 1 cat that started plugging up force the EGR valve wide open. I have also seen the egr pintle spring become weak or break and the EGR valve partially opens at idle or off-idle or opens much more quickly than the PCM is commanding.

Below is the EGR wiring diagram using an 0411. The EGR is controlled on the positive side with an 0411 and the negative side on an older black box. If you do not run the positive wire to the correct pin on the 0411, the EGR recieves a constant 12 volts and the valve fully opens.

You must be registered for see images attach

Yes, I see.

It's just like you said: "The EGR is controlled on the positive side with an 0411 and on the negative side on an older black box".

Specifically...

- On the 0411 provides PWM-switched +12 to the EGR valve's Terminal E. During the 0411 conversion needs to add/confirm this ECU-EGR connection, as you note in Post 789. This differs from 1998 (all black boxes), which simply applies +12V.

- 0411 provides ground to the EGR valve on Terminal A, whereas 1998 (alll blakck boxes) apply the PWM-switched signal there.

- Pintle position sensor is on Terminals BCD, unchanged.

So, of course, if the wiring isn't changed for the 0411 conversion, the EGR valve will still see +12 on Terminal E (from OE wiring) and the new 0411 ECU will GROUND Terminal A, and thus the solenoid will be on constantly and the pintle will be held wide-open for all time.

D@mn dude, you know your $h!t