Dtc P0038 - Mazda 6 2002 Workshop Manual

DTC P0038

DTC P0038 Rear HO2S heater circuit high input
• PCM monitors rear HO2S heater control signal at PCM terminal 4D. If PCM turns rear HO2S heater on but
rear HO2S heater circuit has high voltage, PCM determines that rear HO2S heater circuit has malfunction.
Diagnostic support note
• This is a continuous monitor (O
DETECTION
• MIL illuminates if PCM detects the above malfunction condition in two consecutive drive cycles or in one
CONDITION
drive cycle while the DTC for the same malfunction has been stored in the PCM.
• PENDING CODE is available if PCM detects the above malfunction condition during first drive cycle.
• FREEZE FRAME DATA is available.
• DTC is stored in PCM memory.
• Short to power circuit between rear HO2S terminal D and PCM terminal 4D
POSSIBLE • Rear HO2S or PCM terminal is shorted
CAUSE • Rear HO2S heater malfunction
• PCM malfunction
Diagnostic procedure
STEP
1 PERFORM DTC CONFIRMATION PROCEDURE
• Perform DTC CONFIRMATION PROCEDURE.
(See F–66 DTC CONFIRMATION
PROCEDURE.)
• Is same DTC present?
2 INSPECT REAR HO2S TERMINAL
• Turn ignition key to OFF.
• Disconnect rear HO2S connector.
• Inspect for bent terminals
• Is there any malfunction?
3 INSPECT REAR HO2S HEATER
• Inspect rear HO2S heater.
(See F–56 HEATED OXYGEN SENSOR
(HO2S) INSPECTION.)
• Is rear HO2S heater okay?
F–80
ON-BOARD DIAGNOSTIC
sensor heater).
2
INSPECTION
Yes Go to net step.
No Intermittent concern eists. Go to INTERMITTENT
CONCERN TROUBLESHOOTING procedure.
(See F–227 INTERMITTENT CONCERN
TROUBLESHOOTING.)
Yes Repair or replace terminal, then go to Step 6.
No Go to net step.
Yes Go to net step.
No Replace the rear HO2S, then go to Step 6.
A6E397001084W07
ACTION