engine MAZDA 6 2002 Workshop Manual Suplement

F2–150
ON-BOARD DIAGNOSTIC
DTC P0512A6E407001082236
DTC P0512 Engine switch circuit malfunction
DETECTION
CONDITION•PCM monitors input voltage from engine switch while engine is running. If input voltage from engine switch
is B+ when engine speed is 1,200 rpm or above, PCM determines engine switch circuit malfunction.
POSSIBLE
CAUSE•Engine switch malfunction
•Connector or terminal malfunction
•Short to power circuit in wiring between engine switch terminal A and PCM terminal 57
•PCM malfunction
ENGINE SWITCH
F
AMAIN FUSE
E
FC
DA
B
57 57PCM
4
2
235
ENGINE SWITCH
HARNESS SIDE CONNECTORPCM
HARNESS SIDE CONNECTOR

ON-BOARD DIAGNOSTIC
F2–151
F2
Diagnostic procedure
End Of Sie
STEP INSPECTION ACTION
1VERIFY RELATED REPAIR INFORMATION
AVAILABILITY
•Check for related Service Information
availability.
•Is any related repair information available?Yes Perform repair or diagnosis according to available Service
Information.
•If vehicle is not repaired, go to next step.
No Go to next step.
2INSPECT POOR CONNECTION OF ENGINE
SWITCH CONNECTOR
•Turn engine switch to OFF.
•Inspect for poor connection (damaged, pulled-
out terminals, corrosion, etc.).
•Is there any malfunction?Yes Repair or replace suspected terminal, go to Step 6.
No Go to next step.
3INSPECT ENGINE SWITCH SIGNAL CIRCUIT
FOR SHORT TO POWER
•Turn engine switch to ON (Engine OFF).
•Inspect voltage between engine switch terminal
A and body GND.
•Is voltage below 1.0 V?Yes Go to next step.
No Repair or replace harness for short to power, go to Step 6.
4INSPECT ENGINE SWITCH
•Inspect engine switch.
•Is there any malfunction?Yes Replace engine switch, go to Step 6.
No Go to next step.
5INSPECT POOR CONNECTION OF PCM
CONNECTOR
•Turn engine switch to OFF.
•Inspect for poor connection (damaged, pulled-
out terminals, corrosion, etc.).
•Is there any malfunction?Yes Repair or replace suspected terminal, go to next step.
No Go to next step.
6VERIFY TROUBLESHOOTING OF DTC P0512
COMPLETED
•Make sure to reconnect all disconnected
connectors.
•Clear DTC from PCM memory using WDS or
equivalent.
•Start engine.
•Is same DTC present?Yes Replace PCM, go to next step.
(See F2–64 PCM REMOVAL/INSTALLATION)
No Go to next step.
7VERIFY AFTER REPAIR PROCEDURE
•Perform “After Repair Procedure”.
(See F2–86 AFTER REPAIR PROCEDURE)
•Is there any DTC present?Yes Go to applicable DTC inspection.
(See F2–87 DTC TABLE)
No Troubleshooting completed.

F2–152
ON-BOARD DIAGNOSTIC
DTC P0564A6E407001082237
Diagnostic procedure
DTC P0564 Cruise control signal malfunction
DETECTION
CONDITION•PCM monitors input voltage from cruise control switch while engine is running. PCM determines cruise
control signal malfunction if input voltage from cruise control switch is as following for 120 s:
—Below 0.1 V.
—1.4—1.9 V.
—3.7—3.9 V.
—4.5—4.6 V.
POSSIBLE
CAUSE•Cruise control switch malfunction
•Connector or terminal malfunction
•Short to GND in wiring between cruise control switch terminal B and PCM terminal 64
•Cruise control switch signal and GND circuits short each other
•Open circuit in wiring between cruise control switch terminal B and PCM terminal 64
•Open circuit in wiring between cruise control switch terminal C and PCM terminal 91
•PCM malfunction
STEP INSPECTION ACTION
1VERIFY RELATED REPAIR INFORMATION
AVAILABILITY
•Check for related Service Information
availability.
•Is any related repair information available?Yes Perform repair or diagnosis according to available Service
Information.
•If vehicle is not repaired, go to next step.
No Go to next step.
CRUISE CONTROL SWITCH
PCM
B
C64
91
CRUISE CONTROL SWITCH
HARNESS SIDE CONNECTORPCM
HARNESS SIDE CONNECTOR
BC
64 91
2
2
543
4
7
6
78

ON-BOARD DIAGNOSTIC
F2–153
F2
End Of Sie
2INSPECT POOR CONNECTION OF CRUISE
CONTROL SWITCH CONNECTOR
•Turn engine switch to OFF.
•Inspect for poor connection (damaged, pulled-
out terminals, corrosion, etc.).
•Is there any malfunction?Yes Repair or replace suspected terminal, go to Step 9.
No Go to next step.
3INSPECT CRUISE CONTROL SWITCH SIGNAL
CIRCUIT FOR SHORT TO GND
•Turn engine switch to OFF.
•Inspect continuity between cruise control
switch terminal B and body GND.
•Is there continuity?Yes Repair or replace harness for short to GND, go to Step 9.
No Go to next step.
4INSPECT CRUISE CONTROL SWITCH CIRCUIT
FOR SHORT WITH EACH OTHER
•Turn engine switch to OFF.
•Inspect continuity between cruise control
switch terminals B and C.
•Is there continuity?Yes Repair or replace harness for short with each other, go to
Step 9.
No Go to next step.
5INSPECT CRUISE CONTROL SWITCH SIGNAL
CIRCUIT FOR OPEN
•Turn engine switch to ON. (Engine OFF)
•Inspect voltage at cruise control switch terminal
B (harness side).
•Is voltage below 1.0 V?Yes Repair or replace harness for open, go to Step 9.
No Go to next step.
6INSPECT CRUISE CONTROL SWITCH
•Inspect cruise control switch.
•Is there any malfunction?Yes Replace cruise control switch, go to Step 9.
No Go to next step.
7INSPECT POOR CONNECTION OF PCM
CONNECTOR
•Turn engine switch to OFF.
•Inspect for poor connection (damaged, pulled-
out terminals, corrosion, etc.).
•Is there any malfunction?Yes Repair or replace suspected terminal, go to Step 9.
No Go to next step.
8INSPECT CRUISE CONTROL SWITCH GND
CIRCUIT FOR OPEN
•Turn engine switch to OFF.
•Inspect continuity between cruise control
switch terminal C and PCM terminal 91.
•Is there continuity?Yes Go to next step.
No Repair or replace harness for open, go to next step.
9VERIFY TROUBLESHOOTING OF DTC P0564
COMPLETED
•Make sure to reconnect all disconnected
connectors.
•Clear DTC from PCM memory using WDS or
equivalent.
•Start engine.
•Is same DTC present?Yes Replace PCM, go to next step.
(See F2–64 PCM REMOVAL/INSTALLATION)
No Go to next step.
10VERIFY AFTER REPAIR PROCEDURE
•Perform “After Repair Procedure”.
(See F2–86 AFTER REPAIR PROCEDURE)
•Is there any DTC present?Yes Go to applicable DTC inspection.
(See F2–87 DTC TABLE)
No Troubleshooting completed. STEP INSPECTION ACTION

F2–156
ON-BOARD DIAGNOSTIC
DTC P0661A6E407001082241
Diagnostic procedure
DTC P0661 VSC solenoid valve circuit low input
DETECTION
CONDITION•PCM monitors input voltage from VSC solenoid valve while engine is running. If input voltage from VSC
solenoid valve is below 0.1 V, PCM determines suction control valve circuit low input.
POSSIBLE
CAUSE•VSC solenoid valve malfunction
•Connector or terminal malfunction
•Short to GND in wiring between VSC solenoid valve terminal A and PCM control relay terminal C
•Short to GND in wiring between VSC solenoid valve terminal B and PCM terminal 101
•Open circuit in wiring between VSC solenoid valve terminal PCM control relay terminal C
•Open circuit in wiring between VSC solenoid valve terminal B and PCM terminal 101
•PCM malfunction
STEP INSPECTION ACTION
1PERFORM DTC CONFIRMATION PROCEDURE
•Perform “DTC Confirmation Procedure”.
(See F2–85 DTC CONFIRMATION
PROCEDURE)
•Is same DTC present during KOEO or KOER
self-test?Yes Go to next step.
No Intermittent concern exists. Go to “Intermittent Concern
Troubleshooting”.
(See F2–227 INTERMITTENT CONCERN
TROUBLESHOOTING)
A
B VSC SOLENOID VALVEPCM
101 A B3
632
6
5101
4
2
PCM CONTROL RELAY
TERMINAL C
VSC SOLENOID VALVE
HARNESS SIDE CONNECTORPCM
HARNESS SIDE CONNECTOR

ON-BOARD DIAGNOSTIC
F2–157
F2
End Of Sie
2INSPECT POOR CONNECTION OF VSC
SOLENOID VALVE CONNECTOR
•Turn engine switch to OFF.
•Inspect for poor connection (damaged, pulled-
out terminals, corrosion, etc.).
•Is there any malfunction?Yes Repair or replace suspected terminal, go to Step 7.
No Go to next step.
3INSPECT VSC SOLENOID VALVE CIRCUIT FOR
SHORT TO GND
•Turn engine switch to OFF.
•Inspect continuity between following
harnesses:
—VSC solenoid valve terminal A and PCM
control relay terminal C.
—VSC solenoid valve terminal B and PCM
terminal 101.
•Is there continuity?Yes Repair or replace harness for short to GND, go to Step 7.
No Go to next step.
4INSPECT VSC SOLENOID VALVE
•Inspect VSC solenoid valve.
(See F2–42 VARIABLE SWIRL CONTROL
(VSC) SOLENOID VALVE INSPECTION)
• Is there any malfunction?Yes Replace VSC solenoid valve, go to Step 7.
No Go to next step.
5INSPECT POOR CONNECTION OF PCM
CONNECTOR
•Turn engine switch to OFF.
•Inspect for poor connection (damaged, pulled-
out terminals, corrosion, etc.).
•Is there any malfunction?Yes Repair or replace suspected terminal, go to Step 7.
No Go to next step.
6INSPECT VSC SOLENOID VALVE CIRCUIT FOR
OPEN
•Turn engine switch to OFF.
•Inspect continuity between following
harnesses:
—VSC solenoid valve terminal A and PCM
control relay terminal C.
—VSC solenoid valve terminal B and PCM
terminal 101.
•Is there continuity?Yes Go to next step.
No Repair or replace harness for open, go to next step.
7VERIFY TROUBLESHOOTING OF DTC P0661
COMPLETED
•Make sure to reconnect all disconnected
connectors.
•Clear DTC from PCM memory using WDS or
equivalent.
•Start engine.
•Is same DTC present?Yes Replace PCM, go to next step.
(See F2–64 PCM REMOVAL/INSTALLATION)
No Go to next step.
8VERIFY AFTER REPAIR PROCEDURE
•Perform “After Repair Procedure”.
(See F2–86 AFTER REPAIR PROCEDURE)
•Is there any DTC present?Yes Go to applicable DTC inspection.
(See F2–87 DTC TABLE)
No Troubleshooting completed. STEP INSPECTION ACTION

F2–158
ON-BOARD DIAGNOSTIC
DTC P0662A6E407001082242
DTC P0662 VSC solenoid valve circuit high input
DETECTION
CONDITION•PCM monitors input voltage from VSC solenoid valve while engine is running. If input voltage from VSC
solenoid valve is above B+, PCM determines suction control valve circuit high input.
POSSIBLE
CAUSE•VSC solenoid valve malfunction
•Connector or terminal malfunction
•Short to power circuit in wiring between VSC solenoid valve terminal B and PCM terminal 101
•PCM malfunction
A
B VSC SOLENOID VALVE
A
B
101101PCM
4
2
235
VSC SOLENOID VALVE
HARNESS SIDE CONNECTORPCM CONTROL RELAY
TERMINAL C
PCM
HARNESS SIDE CONNECTOR

ON-BOARD DIAGNOSTIC
F2–159
F2
Diagnostic procedure
End Of Sie
STEP INSPECTION ACTION
1PERFORM DTC CONFIRMATION PROCEDURE
•Perform “DTC Confirmation Procedure”.
(See F2–85 DTC CONFIRMATION
PROCEDURE)
•Is same DTC present during KOEO or KOER
self-test?Yes Go to next step.
No Intermittent concern exists. Go to “Intermittent Concern
Troubleshooting”.
(See F2–227 INTERMITTENT CONCERN
TROUBLESHOOTING)
2INSPECT POOR CONNECTION OF VSC
SOLENOID VALVE CONNECTOR
•Turn engine switch to OFF.
•Inspect for poor connection (damaged, pulled-
out terminals, corrosion, etc.).
•Is there any malfunction?Yes Repair or replace suspected terminal, go to Step 6.
No Go to next step.
3INSPECT VSC SOLENOID VALVE CIRCUIT FOR
SHORT TO POWER
•Turn engine switch to ON (Engine switch OFF).
•Inspect voltage between VSC solenoid valve
terminal B and body GND.
•Is voltage below 1.0 V?Yes Go to next step.
No Repair or replace harness for short to power, go to Step 6.
4INSPECT VSC SOLENOID VALVE
•Inspect VSC solenoid valve.
(See F2–42 VARIABLE SWIRL CONTROL
(VSC) SOLENOID VALVE INSPECTION)
• Is there any malfunction?Yes Replace VSC solenoid valve, go to Step 6.
No Go to next step.
5INSPECT POOR CONNECTION OF PCM
CONNECTOR
•Turn engine switch to OFF.
•Inspect for poor connection (damaged, pulled-
out terminals, corrosion, etc.).
•Is there any malfunction?Yes Repair or replace suspected terminal, go to next step.
No Go to next step.
6VERIFY TROUBLESHOOTING OF DTC P0662
COMPLETED
•Make sure to reconnect all disconnected
connectors.
•Clear DTC from PCM memory using WDS or
equivalent.
•Start engine.
•Is same DTC present?Yes Replace PCM, go to next step.
(See F2–64 PCM REMOVAL/INSTALLATION)
No Go to next step.
7VERIFY AFTER REPAIR PROCEDURE
•Perform “After Repair Procedure”.
(See F2–86 AFTER REPAIR PROCEDURE)
•Is there any DTC present?Yes Go to applicable DTC inspection.
(See F2–87 DTC TABLE)
No Troubleshooting completed.

F2–160
ON-BOARD DIAGNOSTIC
DTC P0850A6E407001082243
Diagnostic procedure
DTC P0850 Neutral switch circuit malfunction
DETECTION
CONDITION•PCM monitors input voltage from neutral switch while engine is running. If input voltage from neutral switch
does not change when vehicle stops after accelerating to above 60 km/h {37 mph} and decelerating to 0
km/h {0 mph} two times, PCM determines neutral switch circuit malfunction.
POSSIBLE
CAUSE•Neutral switch malfunction
•Connector or terminal malfunction
•Short to GND in wiring between neutral switch terminal A and PCM terminal 56
•Open circuit in wiring between neutral switch terminal B and GND
•Open circuit in wiring between neutral switch terminal A and PCM terminal 56
•PCM malfunction
STEP INSPECTION ACTION
1VERIFY RELATED REPAIR INFORMATION
AVAILABILITY
•Check for related Service Information
availability.
•Is any related repair information available?Yes Perform repair or diagnosis according to available Service
Information.
•If vehicle is not repaired, go to next step.
No Go to next step.
2CLASSIFY MALFUNCTION OF SHORT TO GND
OR OPEN
•Turn engine switch to ON (Engine OFF).
•Engage gear.
•Access CPP/PNP PID using WDS or
equivalent.
•Is CPP/PNP PID OFF?Yes Go to Step 5.
No Go to next step.
A
B
A
B NEUTRAL SWITCH
56PCM
56
3
6
5
5
7
498
NEUTRAL SWITCH
HARNESS SIDE CONNECTORPCM
HARNESS SIDE CONNECTOR

ON-BOARD DIAGNOSTIC
F2–161
F2
End Of Sie
3INSPECT NEUTRAL SWITCH FOR CLOSE
STUCK
•Turn engine switch to ON (Engine OFF).
•Disconnect neutral switch connector.
•Access CPP/PNP PID using WDS or
equivalent.
•Is CPP/PNP PID OFF?Yes Replace neutral switch, go to Step 10.
No Go to next step.
4INSPECT NEUTRAL SWITCH SIGNAL CIRCUIT
FOR SHORT TO GND
•Turn engine switch to OFF.
•Inspect continuity between neutral switch
terminal A and body GND.
•Is there continuity?Yes Repair or replace harness for short to GND, go to Step 10.
No Go to next step.
5INSPECT POOR CONNECTION OF NEUTRAL
SWITCH CONNECTOR
•Turn engine switch to OFF.
•Inspect for poor connection (damaged, pulled-
out terminals, corrosion, etc.).
•Is there any malfunction?Yes Repair or replace suspected terminal, go to Step 10.
No Go to next step.
6INSPECT NEUTRAL SWITCH FOR OPEN
STUCK
•Turn engine switch to ON (Engine OFF).
•Disconnect neutral switch connector.
•Connect jumper wire between neutral switch
connector terminals.
•Access CPP/PNP PID using WDS or
equivalent.
•Is CPP/PNP PID ON?Yes Replace neutral switch, go to Step 10.
No Go to next step.
7INSPECT NEUTRAL SWITCH GND CIRCUIT
FOR OPEN
•Turn engine switch to OFF.
•Inspect continuity between neutral switch
terminal B and body GND.
•Is there continuity?Yes Go to next step.
No Repair or replace harness for open, go to Step 10.
8INSPECT POOR CONNECTION OF PCM
CONNECTOR
•Turn engine switch to OFF.
•Inspect for poor connection (damaged, pulled-
out terminals, corrosion, etc.).
•Is there any malfunction?Yes Repair or replace suspected terminal, go to Step 10.
No Go to next step.
9INSPECT NEUTRAL SWITCH SIGNAL CIRCUIT
FOR OPEN
•Turn engine switch to OFF.
•Inspect continuity between neutral switch
terminal A and PCM terminal 56.
•Is there continuity?Yes Go to next step.
No Repair or replace harness for open, go to next step.
10VERIFY TROUBLESHOOTING OF DTC P0850
COMPLETED
•Make sure to reconnect all disconnected
connectors.
•Clear DTC from PCM memory using WDS or
equivalent.
•Start engine.
•Is same DTC present?Yes Replace PCM, go to next step.
(See F2–64 PCM REMOVAL/INSTALLATION)
No Go to next step.
11VERIFY AFTER REPAIR PROCEDURE
•Perform “After Repair Procedure”.
(See F2–86 AFTER REPAIR PROCEDURE)
•Is there any DTC present?Yes Go to applicable DTC inspection.
(See F2–87 DTC TABLE)
No Troubleshooting completed. STEP INSPECTION ACTION