I have just finished a body off restoration of my 1989 Chevrolet Scottsdale 2500 HD.
My question, is there an OBDI or OBDII or do I need a adapter to scan it?
Even if I rebuilt the engine and transmission it has 90 thousand original miles on it before the restoration. Please let me know if there is a way to use my scan tool.
1989 is OBD1, my favorite scanner for this vintage GM product is a Snap-On MT2500, you can find them on eBay fairly reasonable. Be sure the scanner comes with the GM1 aldl adapter, a Primary cartridge and a Troubleshooter cartridge and cables for your model year.
You can short the proper pins (image below) to get the check engine light to flash any codes stored, do this with Key on, Engine off (KOEO). You will get long flashes and short flashes.
Code 12 means there are no codes stored, One long flash followed by 2 short flashes.
Long flashes are the first digit in the number code, followed by short flashes for the second digit.
code - code definition
12- diagnostic mode or no codes present
13- 02 sensor or circuit
14- coolant sensor or circuit/ high temp indicated
15- coolant sensor or circuit/ low temp indicated
16- system voltage out of range
19- crankshaft position sensor or circuit
21- throttle position sensor or circuit- voltage high
22- throttle position sensor or circuit- voltage low
23- mixture control (m/c) solenoid or circuit (carbureted models)
23- manifold air temperature (mat) sensor or circuit (1990 and earlier models)
23- intake air temperature (iat) sensor circuit (fuel-injected models)
24- vehicle speed sensor (vss) or circuit
25- manifold air temperature (mat) sensor or circuit - high temperature indicated (1990 and earlier models)
25- intake air temperature (iat) sensor or circuit - high temperature indicated (1991 and later models)
26- quad driver module circuit
27- quad driver module circuit
28- quad driver module circuit
29- quad driver module circuit
31- park/neutral position (pnp) switch circuit
32- baro sensor or circuit (carbureted models)
32- egr circuit (fuel-injected models)
33- manifold absolute pressure (map sensor signal voltage high
33- mass air flow (maf) sensor or circuit - excessive airflow indicated 34- manifold absolute pressure (map) sensor signal voltage low
34- mass air flow (maf) sensor signal - low airflow indicated
35- idle speed control (isc) switch or circuit (shorted) (carbureted models)
35- idle air control (iac) valve/ circuit
38- brake switch circuit 39- torque converter clutch (tcc) circuit
41- no distributor signals to ecm, or faulty ignition module ( carbed models)
41- cylinders select error- mem-cal or ecm problem ( fuel-injected models 41- cam sensor circuit (3.8 engine)
42- bypass or electronic spark timing (est) circuit
43- low voltage at ecm terminal l (carbureted models)
43- knock sensor circuit
44- oxygen sensor or circuit - lean exhaust detected
45- oxygen sensor or circuit - rich exhaust detected
46- power steering pressure switch circuit
48- misfire diagnosis
51- prom, mem-cal or ecm problem
52- calpak or ecm problem
53- egr fault (carbureted models only)
53- system over-voltage (ecm over 17.7 volts)
54- mixture control (m/c) solenoid or circuit (carbureted models)
54- fuel pump circuit (1986 and later models)
55- oxygen sensor circuit or ecm
55- fuel lean monitor (2.2l engine)
61- oxygen sensor signal faulty (possible contaminated sensor)
62- transaxle gear switch signal circuits
63- manifold absolute pressure (map) sensor voltage high (low vacuum detected)
64- manifold absolute pressure (map) sensor voltage low (high vacuum detected)
66- pressure sensor or circuit air conditioning
89 is OBD1 and requires specific connectors and a OBD1 scantool. You can jump pins A & B on the ALDL (Assembly Line Datalink Connector located under the driver side dash) to make the MIL flash out codes.
