GM OBD1 Codes Retrieval For Pre 1996 GM Vehicles

GM 1983-95 vehicles OBD1 codes self-retrieval

As the name implies, you can get the codes for GM cars or trucks yourself if the model of your vehicle is made before 1995, this means as soon as you see “check engine light” in your dash, you can get the code in minutes if you want.

Shown on the left is a picture of the connector pin terminals where you can get the GM OBD1 code.

When you find this adapter connector (usually on the bottom left side of your dash panel) use a jumper wire or paper clip and connect terminals A and B. Next turn your key on but don't start. Watch your check engine flash the code/s.

EXAMPLE: CODE 12: one long flash and two short flashes CODE 13: one long flash and 3 short flashes.

Note: code 12 is usually the first code you get and just ignore it. Watch the code after code 12, that's what you need to fix.

GM OBD1 Decoder

GM common codes for OBD1 (for vehicles made before 1995)
12 System normal
13 oxygen sensor circuit open
14 coolant sensor high resistance or shorted
15 coolant sensor circuit low or open
16 direct ignition system (DIS) fault in circuit
17 cam position sensor fault
18 crank or cam sensor error
19 crank sensor circuit fault
21 tps sensor out of range
22 tps sensor signal voltage low
23 intake air temp sensor out of range, low
24 vehicle speed (vss) sensor circuit fault
25 air temp sensor sensor out of range, high
26 quad-driver module (computer) circuit #1 fault
27 quad-driver module (computer) 2nd gear circuit
28 quad-driver module (computer) circuit #2 fault
29 quad driver module (computer) 4th gear circuit
31 cam position sensor fault
32 egr circuit fault
33 map sensor signal out of range, high
34 map sensor signal out of range, low
35 idle air control sensor circuit fault
36 ignition system circuit error
38 brake input circuit fault
39 clutch input circuit fault
41 cam sensor circuit fault, igntion control circuit fault
42 electronic spark timing (EST) circuit grounded
43 knock sensor
or electronic spark control circuit fault
44 oxygen sensor lean exhaust
45 oxygen sensor rich exhaust
46 pass-key II circuit or ps.pressure switch circuit fault
47 pcm-bcm data circuit
48 misfire diagnosis
51 calibration error, mem-cal, ecm or eeprom failure
52 engine oil temperature circuit, low temperature indicated
53 battery voltage error or egr or pass-key II circuit
54 egr system failure or fuel pump circuit low voltage
55 a/d converter error or pcm not grounded or lean fuel or frounded reference voltage
56 quad-driver module #2 circuit
57 boost control problem
58 vehicle anti-theft system fuel enable circuit
61 a/c system performance or degraded oxygen sensor signal
62 engine oil temperature high temperature indicated
63 oxygen sensor right side circuit open or map sensor out of range
64 oxygen sensor right side lean exhaust indicated
65 oxygen sensor right side rich exhaust indicated
66 a/c pressure sensor circuit low pressure
67 a/c pressure sensor circuit or a/c clutch circuit failure
68 a/c compressor relay circuit failure
69 a/c clutch circuit head pressure high
70 a/c refrigerant pressure circuit high
71 a/c evaporator temperature sensor circuit low
72 gear selector switch circuit
73 a/c evaporator temperature circuit high
75 digital egr #1 solenoid error
76 digital egr #2 solenoid error
77 digital egr #3 solenoid error
79 vehicle speed sensor (vss) circuit signal high
80 vehicle speed sensor (vss) circuit signal low
81 brake input circuit fault
82 ignition control (IC) 3X signal error
85 prom error
86 analog/digital ecm error
87 eeprom error
99 power management

Please note that after getting any of these codes, you need to reset your vehicle engine computer code. You do that manually by disconnecting the battery negative terminal for 1 minute or two. Then reconnect. Once connected, start and warmed up the engine so you can get the fault code again. If the code that you get initially is the same that you are getting now, then it means that this latest code is a hard or true code that needs immediate attention.

Note:

There are instances that you may disregard the check engine light fault codes. This can be determined especially if the engine has no performance problem (like hesitation or using a lot of gas). However, in most cities in North America, the vehicle will not pass an emission test if it has a check engine light code showing up. And this is true for most GM vehicles.

If you want to read GM OBD1 and OBD2 sample fixes that you can get for free, click on the blog link below. It contains lots of GM vehicle fixes with different fault codes which might apply to your vehicle.

GM Vehicles OBD1 Check Engine light Fixes:

Beretta Check Engine Light Code 44

Chevy check engine light codes 18 and 19

Buick LeSabre Check Engine Light Codes P0341 and P0342

 

 


Click here to get more FREE OBD2 check engine light codes "Sample Fixes"

If you have any serious Acura OBD1 or OBD2 fault codes that you want to fix but cannot do it yourself, please click this website link below: