Mazda MX-6 1998, Workshop Manual

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TROUBLESHOOTING [ENGINE CONTROL FS]
STEP
INSPECTION ACTION
8
CHECK FOR SHORT TO POWER CIRCUIT
IN SHIFT LOCK ACTUATOR
• Key off.
• PCM disconnected.
• Disconnect shift lock actuator and cruise
control module to isolate brake switch.
• Key on, engine off.
• Are stoplamps still on?
Yes SERVICE short to power in stoplamp circuit.
RECONNECT PCM, brake switch and other accessories.
RERUN OBD test.
No
SERVICE short in shift lock actuator, cruise control module
or ABS control module.
RECONNECT all components.
RERUN OBD Test.
KOEO P1703
DTC
Brake switch out of self-test range
DESCRIPTION
• DTC P1703 indicates that when the brake pedal was applied and released during KOER
self-test, BOO signal did not cycle high and low.
[Possible Cause]
• Brake pedal not applied and released during KOER • Open to ground or power
self-test • Damaged brake switch
• Brake pedal applied during entire KOER self-test • Damaged PCM
STEP
INSPECTION
ACTION
1
VERIFY BRAKE PEDAL WAS APPLIED
• Was brake pedal applied and released
during KOER self-test?
Yes Go to next step.
No RERUN KOEO self-test.
APPLY and RELEASE brake pedal.
2
CHECK OPERATION OF BRAKE LIGHT
• Apply and release brake pedal several
times and observe brake light operation.
• Do stoplamps operate normally?
Yes Go to next step.
No Go to step 4 if brake light is never on.
Go to step
6
if brake light is always on.
3 CHECK FOR BOO PID CYCLING
• Key on, engine off.
• Access BOO PID.
• Apply and release brake pedal several
times while viewing BOO PID.
Note
• If BOO PID is not accessible, check BOO
circuit.
• Does the BOO PID cycle ON/OFF?
Yes
Go to Pinpoint Test for intermittent KOEO input sensor
wiggle procedure.
No Check the brake switch input circuit.
4 CHECK FOR POWER CIRCUIT TO BRAKE
SWITCH
Note
• Using a 1 2 volt test lamp, verify integrity of
related fuses in fuse panel and check
condition of brake light bulbs before
starting this test.
• Key off.
• Disconnect brake switch.
• Measure power circuit input voltage
between brake switch and chassis ground.
• Is voltage greater than 10 volts?
Yes Go to next step.
No
SERVICE open power circuit to brake switch.
RECONNECT brake switch.
RESET PCM to completely clear DTCs.
c r After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
5 VERIFY INTEGRITY OF BRAKE SWITCH
• Brake switch disconnected.
• Connect digital multimeter test probes to
brake switch terminals at brake switch.
• Apply brake pedal while monitoring
reading.
• Is resistance less than 5.0 ohms?
Yes SERVICE open circuit between brake switch and brake
light ground.
RECONNECT brake switch.
RESET PCM to completely clear DTCs.
tr After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
No REPLACE brake switch.
RECONNECT brake switch.
RESET PCM to completely clear DTCs.
v After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
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