Mazda 6 2002 Workshop Manual page 176

Diagnostic procedure
STEP
1 PERFORM DTC CONFIRMATION PROCEDURE
• Perform DTC CONFIRMATION PROCEDURE.
(See F–66 DTC CONFIRMATION
PROCEDURE.)
• Is same DTC present?
2 INSPECT POOR CONNECTION OF REAR HO2S
CONNECTOR
• Turn ignition key to OFF.
• Disconnect rear HO2S connector.
• Inspect for poor connection (damaged, pulled-
out pins, corrosion, etc.).
• Are there any malfunctions?
3 INSPECT REAR HO2S HEATER
• Inspect rear HO2S heater.
(See F–56 HEATED OXYGEN SENSOR
(HO2S) INSPECTION.)
• Is rear HO2S heater okay?
4 INSPECT REAR HO2S HEATER POWER
CIRCUIT FOR OPEN CIRCUIT
• Turn ignition key to ON (Engine OFF).
• Measure voltage between rear HO2S terminal
C (harness-side) and body ground.
• Is there voltage B+?
5 INSPECT POOR CONNECTION OF PCM
CONNECTOR
• Turn ignition key to OFF.
• Disconnect PCM connector.
• Inspect for poor connection (damaged, pulled-
out pins, corrosion, etc.).
• Are there any malfunctions?
6 INSPECT REAR HO2S HEATER CONTROL
CIRCUIT FOR SHORT TO GROUND
• Inspect continuity between rear HO2S terminal
D (harness-side) and body ground.
• Is there any continuity?
7 INSPECT HREAR HO2S HEATER CONTROL
CIRCUIT FOR OPEN CIRCUIT
• Remove PCM with PCM connector connected.
• Inspect continuity between rear HO2S terminal
D (harness-side) and PCM terminal 4D.
• Is there any continuity?
8 VERIFY TROUBLESHOOTING OF DTC P0037
COMPLETED
• Make sure to reconnect all disconnected
connectors.
• Clear DTC from PCM memory using WDS or
equivalent.
• Perform KOEO/KOER self-test.
(See F–66 KOEO/KOER
• Is same DTC present?
9 VERIFY AFTER REPAIR PROCEDURE
• Perform “After Repair Procedure”.
(See F–66 AFTER REPAIR
• Is there any DTC present?
End Of Sie
ON-BOARD DIAGNOSTIC
INSPECTION
SELF-TEST.)
PROCEDURE.)
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 8.
No Go to net step.
Yes Go to net step.
No Replace rear HO2S, then go to Step 8.
Yes Go to net step.
No Repair or replace harness for open circuit, then go to Step
8.
Yes Repair terminal, then go to Step 8.
No Go to net step.
Yes Repair or replace harness for short to ground, then go to
Step 8.
No Go to net step.
Yes Go to net step.
No Repair or replace harness for open circuit, then go to Step
8.
Yes Replace PCM, then go to net step.
(See F–43 PCM REMOVAL/INSTALLATION.)
No Go to net step.
Yes Go to applicable DTC troubleshooting.
(See F–67 DTC TABLE.)
No Troubleshooting completed.
ACTION
F–79
F