2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 1769
3. Turn ON the ignition, with the engine OFF.
4. Use the scan tool to verify the proper operation of the engine cooling system fans.
5. Turn OFF the ignition.
6. Verify the proper heat range, and the operation of the thermostat. Refer to Thermostat Diagnosis (See: Engine, Cooling and
Exhaust/Cooling System/Testing and Inspection/Symptom Related Diagnostic Procedures/Thermostat Diagnosis).
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the B34 ECT sensor.
2. Ignition OFF for 90 s, test for less than 5 ohm between the low reference circuit terminal A and ground.
瀚慖f greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20
ECM.
3. Ignition ON, verify the scan tool ECT parameter is colder than -39掳C (-38掳F).
瀚慖f greater than the specified range, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the K20 ECM.
4. Install a 3 A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A. Verify the scan tool ECT
parameter is greater than 149掳C (300掳F).
瀚慖f less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace
the K20 ECM.
5. If all circuits test normal, test or replace the B34 ECT sensor.
Component Testing
Measure and record the resistance of the ECT sensor at various ambient temperatures, then compare those measurements to the Temperature vs
Resistance table. Refer to Temperature Versus Resistance (See: Powertrain Management/Computers and Control
Systems/Specifications/Temperature Versus Resistance).
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Engine Coolant Temperature Sensor Replacement (See: Engine, Cooling and Exhaust/Cooling System/Engine - Coolant Temperature
Sensor/Switch/Coolant Temperature Sensor/Switch (For Computer)/Service and Repair)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming
P0120
DTC P0120, P0122, P0123, P0220, P0222, P0223, or P2135
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0120
- Throttle Position (TP) Sensor 1 Circuit
DTC P0122
- Throttle Position (TP) Sensor 1 Circuit Low Voltage
DTC P0123
- Throttle Position (TP) Sensor 1 Circuit High Voltage
DTC P0220
- Throttle Position (TP) Sensor 2 Circuit
DTC P0222
- Throttle Position (TP) Sensor 2 Circuit Low Voltage
