Mazda 626 Station Wagon, Workshop Manual

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ON-BOARD DIAGNOSTIC
DTC P1498
Except for GF4A-EL Models
DTC P1498 EGR valve motor coil 3 open or short
DETECTION
CONDITION
PCM monitors EGR valve coil control signal at PCM terminal 46. If PCM turns EGR valve coil on and
off but voltage at PCM terminal 46 does not change, PCM determines that EGR valve circuit has
malfunction.
POSSIBLE
CAUSE
EGR valve malfunction
Connector or terminal malfunction
Short to ground circuit in wiring between EGR valve terminal B and PCM terminal 46
Open circuit in wiring between EGR valve terminal B and PCM terminal 46
Open circuit in wiring between main relay terminal D and EGR valve terminal D
PCM malfunction
FROM
MAIN RELAY
T E R M IN A L D PCM
EG R VALVE
\
B D
|
PCM
46
IT I I I I I I I
1
I IT r I I I I I I I I I I I I J
H A R N E S S SID E C O N N E C TO R
(VIEW FRO M T E R M IN A L SIDE)
HARNESS SIDE CO N N E C TO R
(VIEW FROM T ER M IN A L SIDE)
Diagnostic procedure
STEP INSPECTION ACTION
1 VERIFY RELATED REPAIR INFORMATION
AVAILABILITY
• Check for related Service Information
availability.
• Is any 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 CLASSIFY INTERMITTENT CONCERN OR
CONTINUOUS CONCERN
• Turn ignition key to OFF then ON (Engine
OFF).
• Is same DTC present?
Yes
Go to next step.
No
Refer to intermittent concern.
(See F1 -142 No.26 INTERMITTENT CONCERNS)
3 CLASSIFY POWER CIRCUIT OR CONTROL
CIRCUIT MALFUNCTION
• Are same DTC and P1499 present?
Yes
Malfunction at EGR value or power circuit.
Go to next step.
No Malfunction at EGR valve or control circuit.
Go to Step 6.
4 INSPECT POOR CONNECTION OF EGR
VALVE
• Turn ignition key to OFF.
• Disconnect EGR valve connector.
• Check for poor connection (damaged,
pulled-out terminals, corrosion, etc.).
• Are there any malfunctions?
Yes Repair or replace terminals, then go to Step 11.
No Go to next step.
F 1-76