Mazda 626 Station Wagon, Workshop Manual

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ON-BOARD DIAGNOSTIC
Diagnostic p ro c e d u re
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 repair
information.
• If vehicle is not repaired, go to next step.
No Go to next step.
2
VERIFY CURRENT INPUT SIGNAL STATUS-IS
CONCERN INTERMITTENT OR CONSTANT
• Turn ignition key to OFF.
• Connect NGS tester to DLC.
• Start engine.
• Access VS PID using NGS tester.
— Vehicle speed 20 km/h {12 mph}:
20
km/h
{12
mph}
— Vehicle speed 40 km/h {25 mph}:
40 km/h {25 mph}
• Are PID readings within specification?
Yes
Go to intermittent concern troubleshooting procedure.
(See F1-142 INTERMITTENT CONCERN.)
No Go to next step.
3 INSPECT POOR CONNECTION OF VSS
CONNECTOR
• Turn ignition key to OFF.
• Disconnect VSS connector.
• Check for poor connection (damaged/
pulled-out terminals, corrosion, etc.).
• Is connection okay?
Yes Go to next step.
No
Repair or replace pin or connector, then go to Step 9.
4
INSPECT VSS POWER CIRCUIT FOR OPEN
• Verify that VSS connector is disconnected.
• Turn ignition key to ON (Engine OFF).
• Check voltage between VSS terminal C
(harness-side) and ground
• Is battery voltage reading B+?
Yes Go to next step.
No Repair or replace harness, then go to Step 9.
5
INSPECT VSS GROUND CIRCUIT FOR OPEN
• Turn ignition key to OFF.
• Verify that VSS connector is disconnected.
• Check for continuity between VSS terminal A
(harness-side) and ground
• Is there continuity?
Yes
Go to next step.
No Repair or replace harness, then go to Step 9.
6
INSPECT POOR CONNECTION OF PCM
CONNECTOR
• Disconnect PCM connector.
• Check for poor connection (damaged/
pulled-out terminals, corrosion, etc.).
• Is connection okay?
Yes Go to next step.
No Repair or replace pin or connector, then go to Step 9.
7 INSPECT VSS SIGNAL CIRCUIT FOR OPEN
• Disconnect PCM connector and VSS
connector.
• Inspect for continuity between VSS terminal
B and PCM terminal 58.
• Is there continuity?
Yes Go to next step.
No Repair or replace harness, then go to Step 9.
8
INSPECT VSS SIGNAL CIRCUIT FOR SHORT
TO GROUND
• Verity that VSS connector and PCM
connector are disconnected.
• Inspect for continuity between PCM terminal
58 and body ground.
• Is there continuity?
Yes Repair or replace harness, then go to next step.
No Repair VSS, then go to next step.
K 2-67