GM 91-92 3.4L VIN X MFI OBD1 Codes

GM

91-92 3.4L VIN X MFI
13	Oxygen sensor voltage stays between 0.35 and 0.55 volts for 25 seconds. The engine had been running for at least 2 minutes and the TPS was above 4%.
14	Coolant temperature sensor signal indicates a temperature of over 270° F after the engine had been running for 20 seconds.
15	Coolant temperature sensor signal indicates a temperature colder than -37° F when the engine was running.
21	TPS voltage was above 3.78 volts for 1.25 seconds.
22	TPS voltage was under 0.25 volts for 10 seconds when the engine was running.
23	Inlet air temperature sensor signal showed an air temperature of -31° F for 10 seconds after the engine has been running for 4 minutes.
24	Vehicle speed sensor signal showed less than 2 MPH for 3 seconds when throttle position signal was less than 2% with engine speed between 2200 and 4400 RPM with the vehicle in gear.
25	Inlet air temperature sensor signal showed an air temperature of over 293° F and vehicle speed was greater than 1 MPH.
32	EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas.
33	MAP sensor signal voltage was too high (low vacuum) for 5 seconds when throttle opening was under 6%.
34	MAP sensor signal voltage was too low (high vacuum) for 22 seconds when engine speed was under 625 RPM, or when engine speed was over 625 RPM and throttle opening was over 20% for 22 seconds.
35	Idle speed was over 200 RPM outside the desired engine speed commanded by the ECM for 50 seconds.
39	Transaxle clutch switch has failed 4 consecutive times. Vehicle was at normal operating temperature and the speed went from 0 to 40 MPH or more and back to 0 again.
41	MEM-CAL error.
42	The EST signal did not change when the ECM applied bypass voltage to the ignition module.
43	Knock sensor signal voltage was either above 4.8 volts or below 0.64 volts for 10 seconds.
44	Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop operation.
45	Oxygen sensor voltage was over 0.7 volts for 50 seconds of closed loop operation. Engine had been running for at least 1 minute with the throttle angle between 3% and 45%.
51	PROM error.
55	ECM error. Replace ECM.