FixVault

Possible Causes

Possible Causes 
INTERMITTENT DTC
(K99) O2 1/1 HEATER CONTROL CIRCUIT SHORTED TO VOLTAGE
(K99) O2 1/1 HEATER CONTROL CIRCUIT OPEN OR HIGH RESISTANCE
OXYGEN SENSOR 1/1
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Refer to PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE .