Fail-Safe/Backup Function (Limp-In Mode)

When the PCM detects the following malfunction(s), the PCM carries out fail safe/back-up control. In addition, the corresponding Diagnostic Trouble Codes (DTC) number(s) can be identified by using the scan tool.

No cam signal at PCM
- The PCM uses the crankshaft position sensor signal only to control fuel injection timing, etc.
- Accordingly, normal sequential multiport fuel injection may not be carried out.

Front bank O2S stays above center (rich)
- The PCM does not use the oxygen sensor signal.
- The PCM carries out open loop control.

Front bank O2S stays below center (lean)
- The PCM does not use the oxygen sensor signal.
- The PCM carries out open loop control.

Rear bank O2S stays above center (rich)
- The PCM does not use the oxygen sensor signal.
- The PCM carries out open loop control.

Rear bank O2S stays below center (lean)
- The PCM does not use the oxygen sensor signal.
- The PCM carries out open loop control.

Throttle position sensor voltage low
- The PCM uses the value calculated from the MAP sensor signal instead of the throttle valve opening angle (voltage).

Throttle position sensor voltage high
- The PCM uses the value calculated from the MAP sensor signal instead of the throttle valve opening angle (voltage).

Engine coolant temperature (ECT) sensor voltage too low
- The PCM uses the default value [°C (°F)] as the engine coolant temperature.
- The PCM operates the radiator fan.
- The PCM carries out open loop control.

Engine coolant temperature (ECT) sensor voltage too high
- The PCM uses the default value [°C (°F)] as the engine coolant temperature.
- The PCM operates the radiator fan.
- The PCM carries out open loop control.

Front bank O2S stays at center
- The PCM carries out open loop control.

No vehicle speed sensor signal
- The PCM controls the engine as if the vehicle speed were 0 mph.

MAP sensor voltage too low
- The PCM uses the value calculated from the throttle position sensor and the engine speed signals instead of the MAP value (mV).

MAP sensor voltage too high
- The PCM uses the value calculated from the throttle position sensor and the engine speed signals instead of the MAP value (mV).

Slow change in idle MAP sensor signal
- The PCM uses the value calculated from the throttle position sensor and the engine speed signals instead of the MAP value (mV).

Intake air temperature sensor voltage low
- The PCM uses the engine coolant temperature instead of the intake air temperature.

Intake air temperature sensor voltage high
- The PCM uses the engine coolant temperature instead of the intake air temperature.

Front bank O2S shorted to voltage
- The PCM carries out open loop control.

Rear bank O2S stays at center
- The PCM carries out open loop control.

Rear bank O2S shorted to voltage
- The PCM carries out open loop control.

Battery temperature sensor volts out of limit
- The PCM uses the default value [°C (°F)] as the battery temperature.

Low speed fan control relay circuit
- The PCM turns on the high speed fan control relay instead of the low speed fan control relay.

High speed condenser fan control relay circuit
- The PCM turns on the low speed fan control relay instead of the high speed fan control relay.

No 5 volts to MAP sensor
- The PCM uses the value calculated from the throttle position sensor and the engine speed signals instead of the MAP value (mV).

No 5 volts to throttle position sensor
- The PCM uses the value calculated from the MAP sensor signal instead of the throttle valve opening angle (voltage).

Intermittent loss of CMP or CKP
- The PCM uses the crankshaft position sensor signal only to control fuel injection timing, etc. (Accordingly, normal sequential multiport fuel injection may not be carried out.)