Mazda MX-6 1998, Workshop Manual

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TROUBLESHOOTING [ENGINE CONTROL FS]
DTC P0500 Vehicle speed sensor (VSS) malfunction
DESCRIPTION
• DTC P0500 indicates VSS input signal has been detected out of self-test range
[Possible Cause]
• Damaged VSS • Short to ground in VSS (+)/VSS (-) harness circuit
• Damaged PCM • Short to power circuit
• Open in VSS (+)/VSS (-) harness circuit
STEP INSPECTION ACTION
1 CHECK CONTINUITY OF VSS HARNESS
CIRCUIT
• Key off.
• Disconnect PCM. Inspect for damaged or
pushed out pins, corrosion, loose wires,
etc. Service as necessary.
• Install breakout box. PCM disconnected.
• Disconnect VSS.
• Measure resistance between Test Pin 58 at
breakout box and VSS (+) circuit at VSS
connector.
• Measure resistance between Test Pin
33
at
breakout box VSS (-) circuit at VSS
connector.
• Is each resistance less than 5.0 ohms?
Yes Go to next step.
No SERVICE open in harness circuit.
REMOVE breakout box.
RECONNECT all components.
RESET PCM to completely clear DTCs.
id* After Repair Procedure
COMPLETE OBD II Drive Mode.
RUN VSS Drive Mode to verify repair.
2 CHECK VSS HARNESS CIRCUITS FOR
SHORTS TO SIG RTN AND GROUND
• Key off.
•
VSS disconnected.
• Breakout box installed. PCM disconnected.
• Measure resistance between Test Pin 58
and Test Pins 51, 103, 33, 91 and 71 at
breakout box.
• Measure resistance between Test Pins 33
and 71 at breakout box.
• Is each resistance greater than 500
ohms?
Yes Go to next step.
No
SERVICE short circuit.
REMOVE breakout box.
RECONNECT all components.
RESET PCM to completely clear DTCs.
tr After Repair Procedure
COMPLETE OBD II Drive Mode.
RUN VSS Drive Mode verify repair.
3 CHECK VSS RESISTANCE
•
Key off.
• VSS disconnected.
•
Measure VSS resistance.
•
Is resistance between 1 90 and 250
ohms?
Yes REMOVE breakout box.
REPLACE PCM.
RECONNECT VSS.
RUN VSS Drive Mode verify repair.
No REPLACE VSS.
REMOVE breakout box.
RECONNECT PCM.
RUN VSS Drive Mode verify repair.
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