Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information ECM-2820

Condition




The engine control module (ECM) controls preheating by pulsing the current to the positive temperature coefficient (PTC) element in the front heated oxygen sensor (HO2S). Pulse lengths are dependent on the temperature of the heated oxygen sensor (HO2S).
The diagnostic trouble code (DTC) (Signal too high) is stored if the engine control module (ECM) registers that the signal is higher than a certain value during active preheating.
The diagnostic trouble code (DTC) (Signal too low/signal missing) is stored if the engine control module (ECM) registers that the signal is lower than a certain value during deactivated preheating.

Substitute value
- The fuel trim is shut off.

Possible source

Signal too high
- Short-circuit to supply voltage in the signal cable
- Damaged front heated oxygen sensor (HO2S).

Signal too low
- Short-circuit to ground in the signal cable
- Damaged front heated oxygen sensor (HO2S).

Signal missing
- Contact resistance and oxidation in the terminals
- Open-circuit in the power supply from the system relay
- Damaged front heated oxygen sensor (HO2S).

Fault symptom[s]
- Malfunction indicator lamp (MIL) lit.