Mazda MX-6 1998, Workshop Manual

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TROUBLESHOOTING [ENGINE CONTROL KL]
KOEO P1703
DTC
Brake switch out of self-test range
DESCRIPTION
• DTC P1703 indicates voltage was seen at brake switch input during KOEO self-test.
[Possible Cause]
• Brake pedal applied during KOEO self-test • Damaged brake switch
• Brake switch input Test Pin shorted to power circuit
STEP INSPECTION ACTION
1 VERIFY BRAKE PEDAL WAS NOT APPLIED
• Was brake pedal applied during KOEO
self-test?
Yes RERUN KOEO Self-Test.
Avoid applying brake pedal during test.
No Go to next step.
2
CHECK OPERATION OF BRAKE LIGHT
• Apply and release brake pedal several
times and observe brake light operation.
• Does brake light 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 PCM 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 BOO PID cycle ON/OFF?
Yes Go to Pinpoint Test for intermittent KOEO Input sensor
wiggle procedure.
No Check BOO circuit.
4 CHECK FOR POWER TO BRAKE SWITCH
Note
• Using 12 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 switch.
RESET PCM to completely clear DTCs.
tr 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.
i
i t
After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
No REPLACE brake switch.
RECONNECT brake switch.
RESET PCM to completely clear DTCs.
in? After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
6 VERIFY BRAKE SWITCHES NOT ALWAYS
CLOSED
• Key off.
• Brake switch disconnected.
• Key on, Engine off.
• is brake light still on?
Yes Go to next step.
NO
VERIFY proper installation of brake switch. If okay,
REPLACE brake switch.
RECONNECT brake switch.
RESET PCM to completely clear DTCs.
c r After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
7 CHECK FOR SHORT TO POWER CIRCUIT
IN PCM
• Key off.
• Brake switch disconnected.
• Key on.
• Is brake light still on?
Yes Go to next step.
No REPLACE PCM.
RECONNECT brake switch.
RERUN OBD Test.
0 1 -0 1 B -1 2 5