Mazda 626 Station Wagon, Workshop Manual, Page: 66 / 577

ON-BOARD DIAGNOSTIC
DTC P0112
Except for GF4A-EL Models
DTC P0112
IAT circuit low input
DETECTION
CONDITION
PCM monitors IAT sensor signal at PCM terminal 39. If PCM detects IAT sensor voltage
below
0.2 V, PCM determines that IAT sensor circuit has malfunction.
POSSIBLE
CAUSE
• IAT sensor malfunction
• Short to ground circuit between IAT sensor terminal A and PCM terminal 39
• Short each harness IAT signal circuit and IAT ground circuit.
• PCM malfunction
PCM
(VIEW FRO M T ER M IN A L SIDE)
(VIEW FRO M TERM INAL SIDE)
Diagnostic procedure
STEP INSPECTION ACTION
1 VERIFY RELATED REPAIR INFORMATION
AVAILABILITY
• Check for related Service Information
availability.
• Is any related Service information available?
Yes Perform repair or diagnosis according to available
Service information.
• If vehicle is not repaired, then go to next step.
No Go to next step.
2 VERIFY CURRENT INPUT SIGNAL STATUS- IS
CONCERN INTERMITTENT OR CONSTANT
• Turn ignition key to ON (Engine OFF).
• Access IAT V PID using NGS tester.
• Is IAT V PID below 0.2 V?
Yes
Go to next step.
No Intermittent concern is existing. Go to
INTERMITTENT CONCERN TROUBLESHOOTING
procedure.
(See F1-142 No.26 INTERMITTENT CONCERNS)
3 INSPECT MAF SENSOR TERMINAL
• Turn ignition key to OFF.
• Disconnect IAT sensor connector.
• Check IAT sensor terminals A and B
(part-side) for bent.
• Is there any malfunction?
Yes
Repair or replace terminal, then go to Step 7.
No Go to next step.
4 CLASSIFY IAT SENSOR MALFUNCTION OR
HARNESS MALFUNCTION
• Disconnect IAT sensor connector.
• Turn ignition key to ON (Engine OFF).
• Access IAT V PID using NGS tester.
• Is IAT V PID
below 0.2 V?
Yes Go to next step.
No
Replace IAT sensor, then go to Step 7.
F1-45