Mazda 6 2002 - Page 172

ON-BOARD DIAGNOSTIC
F75
F
Diagnostic procedure
STEP INSPECTION ACTION
1 PERFORM DTC CONFIRMATION PROCEDURE
• Perform DTC CONFIRMATION PROCEDURE.
(See F66 DTC CONFIRMATION
PROCEDURE.)
• Is same DTC present?
Yes Go to next step.
No Intermittent concern exists. Go to INTERMITTENT
CONCERN TROUBLESHOOTING procedure.
(See F227 INTERMITTENT CONCERN
TROUBLESHOOTING.)
2 INSPECT POOR CONNECTION OF FRONT
HO2S CONNECTOR
• Turn ignition key to OFF.
• Disconnect front HO2S connector.
• Inspect for poor connection (damaged, pulled-
out pins, corrosion, etc.).
• Are there any malfunctions?
Yes Repair or replace terminal, then go to Step 8.
No Go to next step.
3 INSPECT FRONT HO2S HEATER
• Inspect front HO2S heater.
(See F56 HEATED OXYGEN SENSOR
(HO2S) INSPECTION.)
• Is front HO2S heater okay?
Yes Go to next step.
No Replace front HO2S, then go to Step 8.
4 INSPECT POWER CIRCUIT OF FRONT HO2S
HEATER FOR OPEN CIRCUIT
• Turn ignition key to ON (Engine OFF).
• Measure voltage between front HO2S terminal
C (harness-side) and body ground.
• Is voltage B+?
Yes Go to next step.
No Repair or replace harness for open circuit, then go to Step
8.
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?
Yes Repair terminal, then go to Step 8.
No Go to next step.
DTC P0031 Front HO2S heater circuit low input