Does anyone know what these codes are the came off a C68 electronic in an 88.



-01 (35)



-02 (104)



-03 (65)



-04 (00)



-05 (63)



-06 (154)



-07 (155)



-08 (00)



-09 (80)



Thanks

 

You were actually able to get codes? How did you get into the diagnostic mode? My '87 C68 refuses to go into it, but I have found multiple directions for how to get into it so I'm not sure what is right (if either even is).

 

I have an 88 vert the GM electrical diagnosis service manual states.

To operate the heater and A/C controll assy in the Diagnostic mode. press and hold down the rear defog button, then press and release the blower manual up button. ( for a convertible press EXT Temp then press and release Auto fan ).

 

There are 12 Diagnostic Modes (through '89) and that's what the first number in your Post indicates. System Faults are Diagnostic Mode 8. The 00 means there are none. To get to Diagnostics. Hold the Outside Temp Button and push and release the Auto Fan Button. Press Warm to page through the Modes until its at 8. Push the Cool Button for any faults which are: 00 - none; 01 - Air Mix Valve Feedback is Open; 02 - Outside Air Temp Sensor is open; 04 - Outside Air Temp Sensor is shorted; 08 - Inside Temp Sensor is open; 16 - Inside Temp Sensor is shorted. If a fault is present, the Outside Air Temp Button should be flashing.

The other Mode #'s you have captured are (and realistically, there is no useful information given in these Modes): 1 - Program #; 2 - In Vehicle Thermistor (Temp Sensor); 3 - Ambient Correction; 4 - Blower #; 5 - Outside Temp Thermistor (Sensor); 6 - Feedback Position (of the temp door; 7 - Calculated (Temp) Door Position; 9 - Ratiometric (Temp Door) Feedback Position.

The other 3 Modes are: 10 - Full Hot (Temp Door) Position; 11 - Full Cold (Temp Door) Position; 12 - Software Version.

There really isn't much to help you diagnose a problem - '90 and the later years are much better, adding ECM diagnostics with even more troubleshooting info. Most a/c problems are low or no gas, air flow/blower motor (no codes) and air temp problems due to broken linkage between the air temp door and the electric motor that controls it. Code 1 will only capture the latter if the wire between the motor and the panel is open. Of course, the wire is fine and the motor is working, but the door isn't moving because the linkage is broken.

Hope this helps.

 

Mine won't go into it either. This POS Ac system.

 

The only problem i have is the doors will not work period. I get air out the center vent and defroster only no where else don't matter what button i push. Now it does go between heat and cold when i turn on the heater it gets hot and when i switch to A/C it gets cold. No vents move other than that.

 

You have a vacuum problem - either from the Source - Programmer - or the Control Assembly isn't communicating with the Programmer. Unfortunately, there are no codes. Start at the source - Intake Plenum next to the Fuel Pressure Regulator source - and trace that line to the left of the distributor where it tees into a check valve. Verify that the check valve is good by making sure air only passes in the direction of the firewall. Follow the split from the Tee to cruise and the Vaccum Tank and make sure it's in good shape. Apply 10 inches of vaccum to the Tank to make sure that it holds vacuum. Find the Programmer above the accelerator and remove it. The Black line is the source from the Firewall. Verify Vacuum. If it's there, 9 out of 10 times the Programmer isn't working. It's kinda of crap shoot because there is no way to measure the signal from the Assembly that you want it to switch vacuum to a different door solenoid. You can check the white wire at the Programmer for a 5 volt reference, but that's about it. You can also see if the Vacuum is making it to any of the three solenoids that control door position. They're mounted on the Heater Box next to the Programmer. With the Controls set on Defrost, there should be vacuum on the Tan Line to the Defrost Solenoid. With everything off, there should be vacuum on the Red line to the same solenoid. At Bi-Level, it should have vacuum on the Dark Blue line to the a/c door AND on the Pink line to the heater door. A/C or Econ, Dark Blue and Red; Heat, Pink & Red. To test any of these, the Programmer has to be held vertically - better to just leave it installed and to check for vacuum at the solenoid.

 

PS: Remote possibility that the Defroster door is stuck - that could happen if the pivot rod is rusted or corroded which might occur if the Evaporator is leaking allowing ice to form. Leaking evaporators are common, stuck doors though aren't.

 

I will do as you stated but have done some already. First i have a sears hand vaccum pump i have checked everything from under the hood with the vaccum pump no leaks or anything. I put a vaccum gage on each line and was getting a good vaccum everywhere under the hood no leaks and the check valve i replaced. So as you stated it has to be in the programmer somewhere. My electric motor blend door has to be working since it switches from hot to cold am i correct so far ? I pulled the line off the defroster vaccum canister and hooked my manual vaccum pump to it and it works good open and closes ok. Also hooked my manual vaccum pump to the outside door canister and it works ok also.

 

Everything points to the Programmer and you're right about the temp door - its working as it should. I'd take the Programmer off (only because it's easier for me to remove the vacuum harness with it off) and verify there's vacuum on the Black Line.