|89-91 2.5L VIN R TBI
||Oxygen sensor voltage stays between 0.35 and 0.55 volts for 3 seconds
during closed loop operation after the engine had been running for 40 seconds
and the throttle angle was above 7%. (For the Lumina the oxygen sensor voltage
stays between 0.35 and 0.55 volts for 60 seconds after the engine had been
running for 2 minutes).
||Coolant temperature sensor signal indicates a temperature of over 275°
F for 3 seconds.
||Coolant temperature sensor signal indicates a temperature colder than
-22° F for 60 seconds after the engine has been running for 2 minutes.
||TPS voltage was above 2.5 volts for 2 seconds when the MAP sensor signal
showed manifold vacuum to be 15 pounds or more under 1800 RPM.
||TPS voltage was under 0.2 volts for 2 seconds when the engine was running.
||Inlet air temperature sensor signal showed an air temperature of -31°
F after the engine has been running for 2 minutes.
||When engine speed was between 1400 and 4400 RPM, the MAP sensor signal
showed low voltage (High manifold vacuum) for at least 5 seconds.
||Inlet air temperature sensor signal showed an air temperature over 275°
F for more than 2 seconds after the engine has been running for 5 minutes
and vehicle speed was greater than 44 MPH.
||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.
||MAP sensor signal voltage was too high (low vacuum) for at least 5 seconds
when throttle opening was under 2%.
||MAP sensor signal voltage was too low (high vacuum) when engine speed
was under 1200 RPM or when engine speed was over 1200 RPM with throttle
opening was over 20%.
||Idle speed was over 150 RPM outside the desired engine speed commanded
by the ECM.
||The EST signal did not change when the ECM applied bypass voltage to the
||Oxygen sensor voltage was under 0.2 volts for 60 seconds of closed loop
||Oxygen sensor voltage was above specification. Century and Cutlass Ciera
was over 0.75 volts for 50 seconds in a closed loop. Lumina was over 0.7
volts for 30 seconds and throttle angle was between 3% and 45%.
||Charging system voltage was greater than 16.9 volts for more than 50 seconds.
Repair charging system.