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16.RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
Measure the resistance of the (K900) Sensor ground circuit from the
MAP Sensor harness connector to the appropriate terminal of special
tool #8815.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 17
No>>
Repair the excessive resistance in the (K900) Sensor
ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
17.PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and
Ground circuits.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 310 of 5267

When Monitored:
Ignition on, Engine running, and no ECT DTCs present.
Set Condition:
PCM recognizes that the ECT has failed its self coherence test. The coolanttemp should only change at a
certain rate, if this rate is too slow or too fast this fault will set. Two trip fault. Three good trips to clear MIL.
ETC light will illuminate on first trip failure.
Possible Causes
LOW COOLANT LEVEL
(K2) ECT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
(K2) ECT SIGNAL CIRCUIT OPEN
(K900) SENSOR GROUND CIRCUIT OPEN
(K2) ECT SIGNAL CIRCUIT SHORTED TO GROUND
(K2) ECT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND
THERMOSTAT
ECT SENSOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
NOTE: If this code sets during extreme ambient temperatures, improper installation of a block heater could
be the cause of this DTC.
With a scan tool, read DTCs.
Diagnose all other ECT and Cooling System codes before continuing.
Is the DTC active at this time?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.LOW COOLANT LEVEL
NOTE: If a Engine Coolant Temperature (ECT) DTC is set along with this code,diagnose the ECT DTC first.
NOTE: Inspect the ECT terminals and related PCM terminals. Ensure the terminals are free from corrosion
and damage.
NOTE: The best way to diagnose this DTC is to allow the vehicle to sit overnight outside in order to have
a totally cold soaked engine.
NOTE: Extremely cold outside ambient temperatures may have caused this DTCtoset.
NOTE: Need to make sure that no Cooling System DTCs are set or changes that would make the warm up
much slower or much faster: broken water pump can set this, addition of aftermarket auxiliary cooler can
set this DTC.
WARNING: Never open the cooling system when the engine is hot. The system isunder pressure. Failure to
follow these instructions can result in personal injury or death. Allow the engine to cool before opening the
cooling system.
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Inspect the coolant system for proper level and condition.
Is the coolant level and condition OK?
Ye s>>
Go To 3
No>>
Inspect the vehicle for a coolant leak and add the necessary amount of coolant.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3.THERMOSTAT
NOTE: This test works best if performed on a cold engine (cold soak).
Ignition on, engine not running.
With a scan tool, read the Eng Coolant Tmp Deg value. If the engine was allowed to sit overnight (cold soak), the
temperature value should be a sensible value that is somewhere close to theambient temperature.
NOTE: If engine coolant temperature is above 82°C (180°F), allow the engine to cool until 65°C (150°F) is
reached.
Start the Engine.
During engine warm-up monitor the Eng Coolant Tmp Deg value. The temp deg value change should be a smooth
transition from start up to normal operating temp 82°C (180°F). Also monitor the actual coolant temperature with a
thermometer.
NOTE: As the engine warms up to operating temperature, the actual coolant temperature (thermometer read-
ing) and the Eng Coolant Tmp Deg on the scan tool should stay relatively closetoeachother.
Using the appropriate service information, determine the proper openingtemperature of the thermostat.
Did the thermostat open at the proper temperature?
Ye s>>
Go To 4
No>>
Replace the thermostat.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
4.ECT SENSOR
Connect a jumper between the (K2) ECT Signal circuit and the (K900)
Sensor ground circuit in the ECT Sensor harness connector.
Turn the ignition off.
Disconnect the ECT Sensor harness connector.
With a scan tool, read the ECT voltage.
Is the voltage below 1.0 volt?
Ye s>>
Replace the ECT Sensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
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5.(K2) ECT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Turn the ignition off.
Disconnect the C2 PCM harness connector.
Ignition on, engine not running.
Measure the voltage on the (K2) ECT Signal circuit in the ECT Sensor
harness connector.
Is the voltage above 5.2 volts?
Ye s>>
Repair the short to battery voltage in the (K2) ECT Signal
circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 6
6.(K2) ECT SIGNAL CIRCUIT OPEN
Turn the ignition off.
CAUTION: Do not probe the PCM harness connectors. Probing the
PCM harness connectors will damage the PCM terminals resulting
in poor terminal to pin connection. Install Miller Special Tool #8815
to perform diagnosis.
Measure the resistance of the (K2) ECT Signal circuit from the ECT
Sensor harness connector to the appropriate terminal of special tool
#8815.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 7
No>>
Repair the open in the (K2) ECT Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
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7.(K900) SENSOR GROUND CIRCUIT OPEN
Measure the resistance of the (K900) Sensor ground circuit from the
ECT Sensor harness connector to the appropriate terminal of special
tool #8815.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 8
No>>
Repair the open in the (K900) Sensor ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
8.(K2) ECT SIGNAL CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (K2) ECT Signal circuit
in the ECT Sensor harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (K2) ECT Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 9
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9.(K2) ECT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
Measure the resistance between the (K2) ECT Signal circuit and the
(K900) Sensor ground circuit in the ECT Sensor harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the short between the (K900) Sensor ground and the
(K2) ECT Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 10
10.PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and
Ground circuits.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
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For a complete wiring diagramRefer to Section 8W.
When Monitored:
Ignition on. No Break or APPS faults present.
Set Condition:
The PCM recognizes a brake application following the APPS showing a fixed pedal opening. Temporary or
permanent. Internally the PCM will reduce throttle opening below driver demand. One trip fault and the code
will be set within 5 seconds. ETC light will illuminate, the light will onlystay illuminated while DTC is active.
Possible Causes
CUSTOMER PRESSING ACCLERATOR PEDAL, THEN PRESSING BRAKE PEDAL, AND CONTINUES
HOLDING THEM DOWN SIMULTANEOUSLY
STOP LAMP SWITCH
APP SENSOR
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.DTC INFORMATION
NOTE: If a pedal assembly becomes mechanically stuck the voltage output will stay fixed, if this is also
Followed by a long application of the brakes this code will set.
NOTE: When this code sets the pedal position in the PCM software will ramp toidle. If the Pedal voltage
changes OR the brake pedal is released, the pedal position in the PCM software will ramp up to the pedal
position and the ETC light will go out.
With a scan tool, read DTCs and record the related Freeze Frame data.
Diagnose all other Stop Lamp Switch and APP Sensor codes before continuing.
This code can be set by a driver who uses both feet while driving, one for the Accelerator Pedal and the other for
the Brake Pedal.
NOTE: The most likely cause of this DTC is caused by the customer Brake Torquing the engine by pressing
the Accelerator pedal and the pressing the Brake Pedal.
Ask the driver of the vehicle if these conditions apply to their driving habits.
Are the listed conditions part of the customers driving habits?
Ye s>>
Advise the customer of what caused the DTC. This is normal operation of a ETCequipped vehicle
because of safety issues.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 2
2.STOP LAMP SWITCH OPERATION
With a scan tool, read both Stop Lamp Switch statuses while pressing and releasing the Brake Pedal.
Does the scan tool display the Pressed and Released while pressing and releasing the Pedal?
Ye s>>
Go To 3
No>>
Check the Stop Lamp Switch for proper installation and check the related circuits for opens and shorts
using the appropriate wiring diagram. If OK, replace the Stop Lamp Switch assembly.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
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3.APP SENSOR SWEEP
Ignition on, engine not running.
With a scan tool, monitor both APP Sensor voltage readings.
Slowly press the accelerator pedal from idle until it reaches the end stop near the floor.
APPS No.1 voltage should start at approximately 0.45 of a volt and increaseto approximately 4.6 volts with a
smooth transition.
APPS No.2 voltage should start at approximately 0.22 of a volt and increaseto approximately 2.31 volts with a
smooth transition.
Does the voltage for the appropriate sensor follow the list specification?
Ye s>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Check the Signal and Return circuits for opens and shorts. If OK, Replace the APP Sensor Assembly
per Service Information. After installation is complete, with a scan toolselect the ETC RELEARN func-
tion to relearn the APPS values.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)