Mazda MX-6 1998, Workshop Manual

Page: 228 / 1282

TROUBLESHOOTING [ENGINE CONTROL KL]
KOEO, KOER P0113
DTC P0118
IAT sensor circuit high input
ECT sensor circuit high input
DESCRIPTION
• DTC P0118 (ECT) or P0113 (IAT) indicates corresponding sensor signal is greater than
self-test maximum. Maximum for ECT and IAT sensor is 4.6 volt or -5 0 °C {-4 6 °F}
[Possible Cause]
• Open in harness (IAT or ECT sensor)
• Damaged sensor
• Improper harness connection
• Damaged PCM
STEP INSPECTION
ACTION
1 CHECK ECT AND IAT OUTPUT WITH NGS
TESTER
• Key off.
• Disconnect suspect temperature sensor.
• Connect jum per wire between sensor
signal circuit and ground circuit at
temperature sensor vehicle harness
connector.
• NGS tester installed.
• Key on.
Yes REPLACE suspect sensor.
REMOVE jumper.
RECONNECT vehicle harness.
RERUN OBD Test.
Note
• If any NGS tester communication problem
exists, remove jum per wire immediately
and go to step 3
No REMOVE jumper.
Go to next step.
• Access ECT or IAT PID.
•
Is ECT or IAT PID less than 0.2 volts
(greater than 120 ‘ C {248 ’ F})?
2 CHECK CONTINUITY OF SENSOR SIGNAL
CIRCUIT AND GROUND CIRCUITS
• Key off.
• Disconnect suspected temperature sensor.
• Disconnect PCM. Inspect for damaged or
pushed out pins, corrosion, loose wire, etc.
Service as necessary.
• Install breakout box, leave PCM
disconnected.
• Measure resistance between sensor signal
circuit at temperature sensor vehicle
harness connector and Test Pin 38 or 39 at
breakout box.
• Measure resistance between ground circuit
at temperature sensor vehicle harness
connector and Test Pin 91 at breakout box.
• Is each resistance less than 5.0 ohms?
Yes REMOVE breakout box.
RECONNECT all components.
RERUN OBD Tests.
Go to next step.
No SERVICE open circuit.
REMOVE breakout box.
RECONNECT all components.
RERUN OBD Test.
3 CHECK FOR SENSOR SIGNAL CIRCUIT
SHORTED TO CONSTANT VOLTAGE
• Key off.
• Disconnect suspected temperature sensor.
• Disconnect PCM. Inspect for damaged or
pushed out pins, corrosion, loose wires,
etc. Service as necessary.
• Install breakout box, leave PCM
Yes
REPLACE PCM.
REMOVE breakout box.
RECONNECT all components.
RERUN OBD Test.
disconnected.
• Measure resistance between sensor signal
circuit Test Pin 38 or 39 and constant
voltage circuit at breakout box.
• Is each resistance greater than 10,000
ohms?
No LOCATE and REPAIR short to constant voltage circuit.
RERUN OBD Test.
0 1 -0 1 B -2 2