Hummer H1 Service Manual page 1097

32 PCM/Tech 1 Scan Tool
DTC P0118 - Engine Coolant Temperature (ECT) Sensor Circuit High Voltage
Step
1 Important: Before clearing DTC(s) use the scan tool "Capture Info" to
record Freeze Frame and Failure Record for reference, as data will be lost
when "Clear Info" function is used.
Was the "On-Board Diagnostic (OBD) System Check" performed?
2 1. Scan tool connected.
2. Start the engine.
3. Monitor the ECT display on Scan Tool.
Is the ECT display less than or equal to the specified value?
3 1. Turn the engine "OFF."
2. Turn the ignition "ON."
3. Disconnect the ECT sensor connector.
4. Jumper the ECT harness terminals together.
Does the scan tool display ECT greater than or equal to the specified
value?
4 Jumper the ECT sensor signal circuit to a known good ground. Does the
scan tool display a ECT greater than the specified value?
5 DCT is intermittent. If no other DTC(s) are stored, go to "Diagnostic
Aids".
Are there other DTCs stored?
6 Inspect the sensor connector and PCM connector for a proper connection.
Was a problem found?
7 Check the ECT sensor ground circuit for an open between the ECT sensor
and the PCM.
Was a problem found?
8 Check the ECT sensor signal circuit for an open between the ECT sensor
and the PCM.
Was a problem found?
9 Repair the circuit as necessary.
Is the action complete?
10 Replace the faulty ECT sensor.
Is the action complete?
11 Replace the faulty PCM. NOTE: If the PCM is faulty, the new PCM must
be programmed. Go to PCM replacement and programming procedures.
Is the action complete?
12 1. Using the Scan Tool, select "DTC", "Clear Info".
2. Start engine and idle at normal operating temperature.
3. Select "DTC", "Specific", then enter the DTC which was set.
4. Operate vehicle within the conditions for setting this DTC as specified
in the supporting text.
Does the Scan Tool indicate that this diagnostic Ran and Passed?
13 Using the Scan Tool, select "Capture Info", "Review Info".
Are any DTC's displayed that have not been diagnosed?
_____________________________________________________
Action Value(s) Yes
— Go to Step 2 Go to OBD
-30°C Go to Step 3 Go to Step 5
(-22°F)
151°C Go to Step 6 Go to Step 4
(303°F)
151°C Go to Step 7 Go to Step 8
(303°F)
— Go to
applicable
DTC Table
— Go to Step 9
— Go to Step 9
— Go to Step 9
— Go to Step
12
— Go to Step
12
— Go to Step
12
— Go to Step
13
— Go to
applicable
DTC table
®
No
System Check
Go to
Diagnostic
Aids
Go to Step 10
Go to Step 11
Go to Step 11
—
—
—
—
System OK