Mazda MX-6 1998, Workshop Manual

Page: 138 / 1282

TROUBLESHOOTING [ENGINE CONTROL FS]
CONTINUOUS P1474
DTC
Cooling fan control circuit malfunction
DESCRIPTION
• Continuous Memory DTC P1474 indicates cooling fan control circuit failure has occurred
during vehicle operation
[Possible Cause]
• Open or short cooling fan control circuit • Open power circuit cooling fan relay
STEP INSPECTION ACTION
1 CHECK COOLING FAN CONTROL CIRCUIT
FOR OPEN OR SHORT CIRCUIT
• Key off.
• A/C off.
• NGS tester connected.
• Disconnect cooling fan connector. Inspect
connector for damaged or pushed out pins,
corrosion and loose wires. Service as
necessary.
• Connect non-power test lamp between
cooling fan operational circuit and ground
circuit at vehicle harness connector.
• Key on, engine off.
• Access Output Test Mode on NGS tester.
• Command cooling fan on.
• Observe test lamp for an indication of fault
Yes Key off.
ISOLATE fault and SERVICE as necessary.
RESET PCM to completely clear DTCs.
er
After Repair Procedure
COMPLETE OBD II Drive Mode.
RER UN O BD test.
while performing following (lamp will turn off
when fault detected, indicating open or
short to power):
• Shake, wiggle, bend, cooling fan control
circuit PCM 45 terminal and cooling fan
relay.
• Shake, wiggle, bend, power circuit or
ignition switch circuit to cooling fan relay.
• Lightly tap on cooling fan relay (to
simulate road shock).
• Is fault indicated?
No
Go to next step.
2
CHECK COOLING FAN CONTROL CIRCUIT
FOR SHORT TO GROUND
• Key on, engine off.
• Cooling fan disconnected. Test lamp
installed.
• NGS tester connected.
• Command cooling fan off.
• Observe test lamp for indication of fault
while performing following (lamp will turn on
when fault is indicated, indicating cooling
fan control circuit short to ground):
• Shake, wiggle, bend, cooling fan control
circuit between PCM and cooling fan
relay.
• Lightly tap cooling fan relay (to simulate
road shock).
• Is fault indicated?
Yes ISOLATE fault and service as necessary.
RESET PCM to completely clear DTCs.
c r After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
No Go to ENGINE SYMPTOM TROUBLESHOOTING No. 27.
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