Diagnostic trouble code (DTC) information

Condition 

Diagnostic trouble code (DTC) ECM-4000 is stored if the signal from the canister purge (CP) valve is too high, too low or missing.

Substitute Value 

twin heated oxygen sensor (HO2S) control disabled.

Possible Source 

Signal too high: 

• short-circuit to supply voltage in the signal cable
• defective canister purge (CP) valve

Signal too low: 

• short-circuit to ground in the signal cable

Signal missing: 

• open-circuit in the signal cable
• defective canister purge (CP) valve
• contact resistance in terminals
• open-circuit in power cable

Fault symptom[s] 

• Malfunction indicator lamp (MIL) lit.