Mazda 2002 6 Workshop Manual page 244

DTC P0140 Rear HO2S circuit no activity detected
Diagnostic procedure
STEP
1 PERFORM DTC CONFIRMATION PROCEDURE
• Perform DTC CONFIRMATION PROCEDURE.
(See F–66 DTC CONFIRMATION
PROCEDURE.)
• Is same DTC present?
2 VERIFY RELATED PENDING AND STORED
DTCS
Note
• If fuel monitor DTC, DTC P0131or P0132 is
retrieved, ignore it until P0140 is fixed.
• Turn ignition key to OFF, then ON (Engine
OFF).
• Verify pending and stored DTCs using WDS or
equivalent.
• Is other DTC present?
3 IDENTIFY TRIGGER DTC FOR FREEZE FRAME
DATA
• Is DTC P0140 on FREEZE FRAME DATA?
4 VERIFY CURRENT INPUT SIGNAL STATUS
• Warm up engine.
• Access O2S12 for P0140 or O2S22 for P0160
PID using WDS or equivalent.
• Verify PID while racing engine at least 10
times (in NEUTRAL (MTX) or PARK (ATX)).
• Is PID reading okay?
— More than 0.55 V at least once during
engine racing.
5 INSPECT INSTALLATION OF REAR HO2S
• Check if rear HO2S is loosely installed.
• Is sensor installed securely?
ON-BOARD DIAGNOSTIC
INSPECTION
Yes Go to next step.
No Intermittent concern exists. Go to INTERMITTENT
CONCERN TROUBLESHOOTING procedure.
(See F–227 INTERMITTENT CONCERN
TROUBLESHOOTING.)
Yes Go to appropriate DTC troubleshooting procedures.
(See F–67 DTC TABLE.)
No Go to next step.
Yes Go to next step.
No Go to troubleshooting procedures for DTC on FREEZE
FRAME DATA.
(See F–67 DTC TABLE.)
Yes Go to step 7.
No Go to next step.
Yes Go to next step.
No Install sensor securely, then go to Step 9.
ACTION
F–115
F