Mazda MX-6 1998, Workshop Manual

Page: 135 / 1282

TROUBLESHOOTING [ENGINE CONTROL FS]
DTC P1464 Air conditioner (A/C) demand out of self-test range
DESCRIPTION
• DTC P1464 indicates A/C switch did not turn off during KOER or KOEO self-test
[Possible Cause]
• A/C switch turned on during self-test • Short to ground in A/C relay circuit
STEP INSPECTION
ACTION
1 CHECK FOR KOEO AND KOER SELF-TEST
• Was A/C switch off during KOEO and
KOER self-tests?
Yes Go to next step.
No
RERUN KOEO and/or KOER self-test with A/C switch off.
2
CHECK DTC PRESENT
• Active Continuous Memory self-test.
• Are any DTCs present?
Yes Go to appropriate DTC chart.
No Go to next step.
3 CHECK FOR A/C RELAY CIRCUIT
• Breakout box installed.
• Key on, engine running.
• Fan switch in 1st speed.
• Measure voltage between Test Pin 69 at
breakout box and chassis ground.
• A/C switch ON: 0 V
• A/C switch OFF: 12 V
• Are voltages correct?
Yes CHECK A/C relay operation.
If okay, intermittent poor connection or component
malfunction. (REPAIR or REPLACE as necessary).
Go to SYMPTOM TROUBLESHOOTING No.27.
If okay, REPLACE PCM.
No Go to next step.
4 CHECK FOR A/C SWITCH CIRCUIT
• Measure voltage between Test Pin 41 at
breakout box and chassis ground.
• A/C switch ON: 0 V
• A/C switch OFF: 12 V
• Are voltages correct?
Yes Go to next step.
No Go to step
6
.
5
CHECK CONTINUITY OF A/C RELAY
CIRCUIT
• Key off.
• Disconnect A/C relay and breakout box
from PCM (leave breakout box connected
to PCM vehicle harness connector).
• Measure resistance between Test Pin 69 at
breakout box and chassis ground.
• Is resistance greater than 10,000 ohms?
Yes
Intermittent poor connection or component malfunction
between A/C relay and PCM circuit. (REPAIR or
REPLACE as necessary).
No SERVICE short circuit between A/C relay and PCM.
REMOVE breakout box.
RECONNECT all components.
RERUN OBD Test.
6
CHECK A/C AMPLIFIER
• Perform A/C amplifier inspection.
•
Is A/C amplifier okay?
Yes
Go to next step.
No
REPLACE A/C Amplifier.
7
CHECK CONTINUITY OF A/C SWITCH
CIRCUIT
• Key off.
• Disconnect A/C amplifier and breakout box
from PCM (leave breakout box connected
to PCM vehicle harness connector.)
• Measure resistance between Test Pin 41 at
the breakout box and chassis ground.
• Is resistance greater than 10,000 ohms?
Yes Check heater control unit operation.
If voltage incorrect, REPLACE heater control unit.
If voltage correct, REPLACE PCM.
No
SERVICE short circuit between A/C amplifier and PCM.
REMOVE breakout box.
RECONNECT all components.
RERUN OBD Test.
0 1 -0 1 A -1 07