Mazda MX-6 1998, Workshop Manual

Page: 121 / 1282

TROUBLESHOOTING [ENGINE CONTROL FS]
DTC P1116 ECT sensor input signal out of self-test range
DESCRIPTION
• DTC P1116 (ECT) indicates that corresponding sensor is out of self-test range. Correct
range of measurement is
• -6 .6 "C (20 T ) to 115 ’ C (240 'F } (KOEO)
• 49 °C {120 °F] to 115 'C {240 °F] (KOER)
[Possible Cause]
• Low coolant level • Poor thermostat operation
• Damaged harness connector • Damaged sensor
• Overheated condition
STEP INSPECTION
ACTION
1
CHECK OPERATION, INSTALLATION OF
ENGINE COOLANT TEMPERATURE
SENSOR
• Run engine at 2,000 rpm until engine
temperature stabilizes.
NO START:
• Go to step 3
VEHICLE STALLS:
• Return to Symptom Flow Chart
• Check that upper radiator hose is hot and
pressurized.
• Rerun Key On Engine Running (KOER)
self-test.
• Is DTC P1116 present?
Yes
For symptom of cooling system concern:
Do not service DTC P1116, service next DTC.
If no other DTC’s exists.
RETURN to Symptom Flow Charts.
All others:
Go to next step.
No
Engine was not during closed loop operating condition.
SERVICE other DTCs as necessary.
2 CHECK CONSTANT VOLTAGE CIRCUIT
VOLTAGE AT THROTTLE POSITION
SENSOR
• Key off.
• Disconnect TP sensor.
• Measure voltage between constant voltage
circuit and TP sensor ground circuit at TP
sensor vehicle harness connector.
• Is voltage between 4.5 volts and 5.5
volts?
Yes There is sufficient constant voltage.
RECONNECT TP sensor.
Go to next step.
No REPAIR open in constant circuit.
Go to ENGINE SYMPTOM TROUBLESHOOTING No.31.
3 CHECK RESISTANCE OF ENGINE
COOLANT TEMPERATURE SENSOR WITH
ENGINE OFF
• Key off.
• Disconnect ECT sensor.
• Measure resistance between sensor signal
circuit and TP sensor ground circuit at ECT
sensor.
• Is resistance within specification?
Yes For ECT sensor with NO START:
Do not service DTC P1116 at this time.
RETURN to Symptom Flow Charts.
All others:
Go to next step.
No REPLACE suspect sensor.
RECONNECT vehicle harness.
RERUN OBD Test.
4 CHECK RESISTANCE OF TEMPERATURE
SENSOR WITH ENGINE RUNNING
Note
• Verify engine is at operating temperature
before taking ECT readings.
• Key off.
• Suspect engine coolant temperature
sensor disconnected.
• Run engine for two minutes at 2,000 rpm.
• Measure resistance between sensor signal
circuit and TP sensor ground circuit at
engine coolant temperature sensor.
• Is resistance within specification?
Yes REPLACE PCM.
RECONNECT vehicle harness.
RERUN OBD Test.
No REPLACE suspect sensor.
RECONNECT vehicle harness.
RERUN OBD Test.
0 1 -0 1 A -9 3