GM 87-90 2.0L VIN M MFI OBD1 Codes

GM

87-90 2.0L VIN M MFI
13	Oxygen sensor voltage stays between 0.35 and 0.55 volts for 60 seconds. Engine was at normal operating temperature and had been running for at least 1 minute after start with a throttle angle above 6.5%.
14	Coolant temperature sensor signal indicates a temperature of over 275° F for 3 seconds.
15	Coolant temperature sensor signal indicates a temperature colder than -22° F after engine had been running for 50 seconds.
21	TPS voltage was above 2.5 volts for 10 seconds when the MAP sensor signal showed manifold vacuum to be 15 pounds or more with an engine speed less than 1300 RPM.
22	TPS voltage was under 0.2 volts for 4 seconds when the engine was running.
23	Manifold air temperature sensor signal showed an air temperature below -22° F for 10 seconds.
24	When engine speed was between 1400 and 4400 RPM, the MAP signal showed low voltage (high manifold vacuum) for at least 5 seconds.
25	Inlet air temperature sensor signal showed an air temperature over 275° F for more than 30 seconds.
31	Manifold pressure exceeded 8 psi of boost for 2 seconds.
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 2%.
34	MAP sensor signal voltage was too low (high vacuum) when engine speed was below 1200 RPM and TPS was greater than 20%.
35	Idle speed was 225 RPM above desired speed for 20 seconds.
42	The EST signal did not change when the ECM applied bypass voltage to the ignition module.
43	Knock sensor circuit voltage was above 3.5 volts or below 1.5 volts for 5 seconds.
44	Oxygen sensor voltage was under 0.27 volts for 25 seconds of closed loop operation.
45	Oxygen sensor voltage was over 0.75 volts for 50 seconds or more in closed loop operation.