Diagnostic Trouble Code Descriptions
Description12- No tach signal to ECM.
13- Oxygen sensor circuit. Engine must operate five minutes at part throttle before code will appear.
14- Shorted coolant temperature sensor circuit. Engine has to operate two minutes before code will appear.
15- Open coolant temperature sensor circuit. Engine has to operate at least five minutes at part throttle before code will appear.
21- Throttle position sensor circuit
21 & 22- (At Same Time)- Grounded WOT switch.
22- Grounded adaptive vacuum or WOT switch.
23- Grounded or open carburetor MC solenoid circuit.
44- Either the oxygen sensor circuit is shorted or a carburetor or vacuum hose problem exists. Oxygen sensor voltage represents an extreme lean air/fuel mixture continuously. This causes the ECM to regulate the MC solenoid to produce an extreme rich air/fuel mixture continuously. The engine has to operate for about five minutes at part throttle under load and system in Closed Loop Mode Of Operation before this code will appear.
44 & 45- (At Same Time)-Faulty oxygen sensor.
45- Oxygen sensor voltage represents an extreme rich air/fuel mixture continuously. This causes the ECM to regulate the MC solenoid to produce an extreme lean air/fuel mixture continuously. Either the oxygen sensor circuit is open or there is a carburetor problem. The engine has to operate for about five minutes in the closed Loop Mode Of Operation before this code will appear.
51- Faulty calibration unit (PROM) or incorrect installation.
52 & 53- (At Same Time)-If test bulb is off, it indicates an intermittent ECM problem. If test bulb is on, it indicates a faulty ECM problem.
54- Faulty MC solenoid and/or ECM.
55- Faulty oxygen sensor circuit or ECM.