Code thrown but not for my year/MAP issue

[Jawzjeep]

@gmbellew ya I thought I hit gold when I checked my EGR solenoid and it was bad a while back. Replaced it with a tested new one and I had no issue for a while. EGR works right when manipulated and held vacuum. Getting to the root of why the EGR is being opened at barely any throttle might just have to do with that ground coming from the ECU.

 

[AuroraGirl]

Here I have something important for you, does your 1991 suburban have a 4l60 (700r4)?

Number: 91-149-6E Section: 6E Date: January 1991 Corporate Bulletin No.: 066502R Subject: "SERVICE ENGINE SOON" LIGHT POSSIBLE FALSE CODE 32 Model and Year: ALL 1987-91 TRUCKS WITH 4L60 AUTOMATIC TRANSMISSION (700-R4) TO: ALL CHEVROLET DEALERS Some 1987-91 light duty trucks equipped with 4L60 transmissions may experience a possible false Code 32 - EGR System Malfunction. The customer may not experience a change in performance or driveability with a Code 32 set. If normal EGR diagnostics do not reveal the cause for Code 32, the following steps should be taken to correct the condition: Check the TCC ([1][2]Torque Converter Clutch) engagement solenoid/wiring harness for a short-circuit. 1. Disconnect the TCC harness connector from the left side of the transmission. 2. Measure resistance between TCC transmission connector terminals "A" and "D" with a Digital Volt Ohmmeter (DVOM). Solenoid resistance must measure 20 - 25 ohms at 20 degrees C (68 degrees F). Resistance will be slightly higher if the transmission is at operating temperature. If the resistance is less than 20 ohms the TCC solenoid diode or wiring is shorted and the solenoid must be replaced. 3. With key on, using a DVOM check for voltage at pin "D" of the TCC wiring harness. Voltage greater than one volt should not be found. If voltage exceeding one volt is present, circuit 422 is shorted to voltage and the short must be repaired. Refer to the appropriate service manual for circuit 422 diagnosis and repair. Test operation of the TCC through the use of a scan tool connected to the vehicle ALDL connector. The following conditions must be satisfied when testing TCC operation. ^ Clear stored trouble codes. ^ Engine at normal operating temperature (above 65 degrees C, 149 degrees F) and in closed loop. ^ Constant throttle position. TPS voltage = 1.3 V (minimum = 1.1 V, maximum = 1.5 V). ^ Vehicle speed = 45 mph (minimum = 35 mph, maximum = 55 mph). ^ Brake switch closed (brake pedal not applied). ^ 3rd or 4th gear. Confirmation The scan tool will display the ECM command for TCC engagement when the above conditions are satisfied. When the TCC engages there should be a decrease in engine speed by a minimum of 100 RPM. If TCC operation is normal, it is not necessary to replace the solenoid assembly. After verification of TCC operation, check for stored trouble codes. If TCC fails to engage consult Section 10, Transmission Controls located in Fuel and Emissions Manual and section 7A of the appropriate service manual.

 

[AuroraGirl]

Have I asked you for your VIN op? If i havent, post it and Ill check to see if there is an updated PROM related to your concern from GM as well

 

[Jawzjeep]

Have I asked you for your VIN op? If i havent, post it and Ill check to see if there is an updated PROM related to your concern from GM as well

I will here shortly I'm on my way home

That looks like some pretty good info, thank you. I'm pretty sure I'll have to read that a couple of times to take that all in

 

[Jawzjeep]

@AuroraGirl, yes it has a 700r4. Vin# is 1GKEV16K4MF526631. I appreciate you looking thank you

I'm not that great with electrical and have to look up testing procedures for a lot of the sensors and things but I'm getting better. I don't have any form of scan tool and I've never used one before. I've just been using onboard diagnostics.

If I get it out on the highway and verify torque converter lockup would that eliminate the possibility of the issue you lined out?

 

[AuroraGirl]

@AuroraGirl, yes it has a 700r4. Vin# is 1GKEV16K4MF526631. I appreciate you looking thank you

I'm not that great with electrical and have to look up testing procedures for a lot of the sensors and things but I'm getting better. I don't have any form of scan tool and I've never used one before. I've just been using onboard diagnostics.

If I get it out on the highway and verify torque converter lockup would that eliminate the possibility of the issue you lined out?

If you can, do the OHm check on the sensor harness. The trans wont have many wires going to it so finding it shouldnt be hard.

 

[AuroraGirl]

Also, no new PROMs from gm for your vehicle for addressing any issues, so you should be good. Your truck is a federal emissions or california?

 

[Jawzjeep]

@AuroraGirl the testing will have to wait till tomorrow assuming the weather is going to hold.

Federal emissions or California I'm not positive what that means but I'm assuming you're asking if it has a cat yes it does. If you mean something else please dumb it down for me, lol.

 

[AuroraGirl]

@AuroraGirl the testing will have to wait till tomorrow assuming the weather is going to hold.

Federal emissions or California I'm not positive what that means but I'm assuming you're asking if it has a cat yes it does. If you mean something else please dumb it down for me, lol.

Can you look at your VECI underhood, probably on the core support or the hood, maybe on the air cleaner. (most likely core support) the label will say something like "THIS VEHCILE CONFORMS TO EPA EMISSIONS FOR THE 1991 MODEL YEAR" or "THIS VEHICLE CONFORMS TO CARB/CALIFORNIA EMISSIONS FOR LIGHT DUTY TRUCKS FOR THE 1991 MODEL YEAR"