Hi all Just recently my 89 pontiac T/A with the 350 tpi engine and auto tranny. My engine light keeps coming on. anybody know what could be causing this? Any info would be apparicated thanks

 

Go to your local Autozone and have them scan for codes. They do this for free. This will give you a starting point at what to look at.

 

.....or you could do it yourself.

THE CONNECTOR


-----------------------
| 1 2 3 4 5 6 |
| 7 8 9 10 11 12 |
-----------------------


DISPLAYING THE TROUBLE CODES
Run a wire/hairpin from Pin 6 to Pin 12 with the ignition off (although on later cars it should be from Pin 5 to Pin 6), then turning the ignition to the on position without starting the engine will flash the "Service Engine Soon" light in the following sequence: flash, pause, flash-flash, long pause flash, pause, flash-flash, long pause flash, pause, flash-flash, long pause Following this "12" code repeating three times will come any trouble codes stored, flashing each of them three times. If you do not see the "12" flash three times, your diagnostic circuit is defective.
Some vehicles will display stored trouble codes, then "12" again, followed by energizing "most system controlled relays." The fuel pump relay will not energize. The idle air control valve will fully extend to enable checking minimum idle speed.

CLEARING THE TROUBLE CODES
Turn the keyswitch to the off position. To clear any trouble codes, disconnect the power feed for 30 seconds. If this is done at the battery, and your car stereo is equipped and programmed with a four digit pin code, you may have to re-enter that as well to use your stereo again. A better place to remove power is at the fuse.

TROUBLE CODES


12. No reference pulses to Electronic Control Module (ECM).
13. Oxygen sensor signal stays lean during warm engine cruise
14. High temperature indicated at engine coolant temp. sensor
15. Low temperature indicated at engine coolant temp. sensor
16. High battery voltage OR
Direct inition system open or shorted to ground
17. RPM signal problem
18-20. N/A
21. High voltage at throttle positon sensor
22. Low voltage at throttle positon sensor OR
Fuel cutoff relay circuit open or shorted to ground
23. Low temperature at manifold air temperature sensor OR
Throttle position sensor error
24. Circuit fault in vehicle speed sensor
25. High temperature at manifold air temperature sensor OR
Vacuum switching valve circuit open or shorted to ground OR
High voltage at ATS sensor
26. Fault in quad driver module
27. Fault in 2nd gear switch
28. Fault in 3rd gear switch
29. Fault in 4th gear switch
30. N/A
31. Low voltage at manifold absolute pressure sensor OR
Fuel injector OR
Park or neutral switch OR
CAM diagnostic OR
Governor malfunction OR
Wastegate overboost OR
Wastegate eletrical signal open or shorted to ground
32. Fault in barometric pressure sensor circuit OR
Fault in exhaust gas recirculation valve diagnostic switch OR
Fault in electronic vacuum regulator valve
33. High voltage (low vacuum) at mass air flow sensor (or MAP sensor)
34. Low voltage (high vacuum) at mass air flow sensor (or MAP sensor)
35. Idle speed can not be set to desired RPM
36. Burn off at mass air flow sensor OR
Problem in transmission shift OR
Fault in direct ignition system OR
Missing pulses in electronic spark timing signal
37. N/A
38. Fault in torque converter clutch brake switch
39. Fault in torque converter clutch circuit
40. N/A
41. Fault at cam sensor OR
Cylinder select error OR
Tach input error
42. Fault at electronic spark timing circuit OR
Fault at direct ignition system OR
Fault at fuel cutoff relay circuit
43. Low voltage at electronic spark timing circuit
44. Oxygen sensor lean
45. Oxygen sensor rich
46. Fault at vehicle anti-theft sytem OR
Fault at power steering switch
47. Problem at Electronic Control Module (ECM)
48. Misfire
49. Vacuum leak
50. N/A
51. PROM error
52. Problem at Electronic Control Module (ECM) -
Missing fuel calpac missing OR
Analog to digital converter error OR
Fault at quad driver module OR
Low voltage at oil temperature sensor
53. High voltage at battery OR
High voltage at exhaust gas recirculation valve OR
Voltage reference error OR
Problem at vehicle anti-theft system
54. Low voltage at fuel pump OR
Low voltage at Fuel pump relay OR
Output failure at quad driver module
55. Problem at Electronic Control Module (ECM) -
ECM failure OR
Serial bus error OR
Fuel lean malfunction
56. Low coolant or corrosivity OR
Fault in port throttle system vacuum sensor
57. N/A
58. Problem at vehicle anti-theft system
59-60. N/A
61. Oxygen sensor degraded OR
Port throttle system error OR
Cruise control problems
62. Gear switch input diagnostics OR
High voltage at oil temperature sensor OR
Fault in cruise control- vacuum solenoid circuit
63. High voltage at manifold absolute pressure sensor OR
Fault in exhaust gas recirculation valve OR
Fault at right oxygen sensor
64. Low voltage at manifold absolute pressure sensor OR
Fault in exhaust gas recirculation valve OR
Right oxygen sensor lean
65. Failure at exhaust gas recirculation valve OR
Faulure at injector peak/hold diagnostic OR
Right oxygen sensor rich OR
Fault at cruise control position sensor
66. Internal reset of Electronic Control Module (ECM)
67. Fault at cruise control switch
68. Fault at cruise control switch
69. Fault at air conditioner pressure switch
70-87. N/A
88. Internal reset of Electronic Control Module (ECM)

 

Or if you like diagrams and photos:

First, you'll need to acquire a GM OBD I ECM Diagnostic Trouble Code Retrieval Tool (commonly known as a paper clip to TGO members).

With the engine and ignition turned off, locate the ALDL connector under the dash, just to the right of the steering wheel in the driver's foot well area on Firebirds, and on the left on Camaros. There should be a small rectangular cover over the access hole in the lower dash trim.



Insert a tool as described above (paper clip) into the 'A' and 'B' terminals on the ALDL connector:



WITHOUT STARTING the engine, turn the ignition to the "RUN" position. Watch the Malfunction Indicator Lamp (MIL) - it will begin to flash. This is also commonly called the "Service Engine Soon" or "SES" lamp. The first code will flash three times, and will usually be a code '12'. This is encoded by one flash of the lamp, a brief pause, then two successive flashes of the lamp. Each code will repeat three times, so you should see a "Code 12" flash three times. Any other error codes will follow in numerical order, and each code should flash three times. After all codes have been displayed three times, the "Code 12" will again flash three times, then all other codes will follow as described earlier. This cycle will continue until the jumper is removed or the ignition is turned off.

After you have made a note of all error codes, turn off the ignition and remove the jumper immediately. If you forget to remove the jumper and attempt to start the engine with it in place, you could damage the ECM. For this reason you should remove it immediately.

Once you have a note of all error codes, check this file for the decoding:

GM Error Codes.pdf.

You'll need Adobe Acrobat Reader to open/print the file.

 

Yea go over to autozone and invest in a GM OBI code key 99 cents. The local AZ stoped selling them per say and are giving them away for free I got a hand full for free, cheaper then a paper clip and will fit nicely on a key ring.

 

Thanks everybody for the info i really appriacate it.