2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1765

2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1765

1. If DTC P0480, P0481, P0691, P0692, P0693, or P0694 is set, diagnose that DTC first.

2. Observe the engine coolant level. The engine coolant level should be within the operating range. Refer to Capacities - Approximate Fluid,

and Engine Coolant in the Owner's Manual.

3. Ensure that the vehicle has the correct engine coolant with correct concentration and is not old, contaminated, or contains additives. Refer to

Recommended Fluids and Lubricants in the Owner's Manual.

4. Inspect the cooling system for the following:

* Leaks

* Kinked or pinched hoses, especially at the radiator

* Loose, missing, or damaged radiator air seals or deflectors

* Air flow obstructions or bent fins at the radiator or the A/C condenser-Refer to Symptoms - Engine Cooling (See: Engine, Cooling and

Exhaust/Cooling System/Testing and Inspection/Symptom Related Diagnostic Procedures/Symptoms - Engine Cooling).

Note: A small delay occurs before the ECM changes the cooling fan speed.

5. Command the cooling fans ON and OFF, low and high speed. The engine cooling fans should turn ON and OFF with each command.

瀚慖f the cooling fans do not function as indicated, refer to Cooling Fan Inoperative (LAU) (See: Engine, Cooling and Exhaust/Cooling

System/Testing and Inspection/Symptom Related Diagnostic Procedures/Cooling Fan Inoperative)Cooling Fan Inoperative (LF1) (See:

Engine, Cooling and Exhaust/Cooling System/Testing and Inspection/Symptom Related Diagnostic Procedures/Cooling Fan Inoperative).

Circuit/System Testing

1. Test the thermostat for correct operation. Refer to Thermostat Diagnosis (See: Engine, Cooling and Exhaust/Cooling System/Testing and

Inspection/Symptom Related Diagnostic Procedures/Thermostat Diagnosis).

2. Test the engine cooling system for overheating. Refer to Engine Overheating (See: Engine, Cooling and Exhaust/Cooling System/Testing

and Inspection/Symptom Related Diagnostic Procedures/Engine Overheating).

3. Inspect the water pump and coolant flow for correct operation. Refer to Water Pump Cleaning and Inspection (See: Engine, Cooling and

Exhaust/Engine/Service and Repair/Overhaul/100. Water Pump Cleaning and Inspection).

4. Inspect the engine mechanical for worn, leaking, cracked cylinder heads or engine block. Refer to Coolant in Engine Oil (See: Engine,

Cooling and Exhaust/Engine/Testing and Inspection/Symptom Related Diagnostic Procedures/Coolant in Engine Oil).

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

P1551

DTC P1551

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 Descriptor

DTC P1551

- Throttle Valve Rest Position Not Reached During Learn

Circuit/System Description

The engine control module (ECM) controls the throttle valve by applying a varying voltage to the control circuits of the throttle actuator control

(TAC) motor. The ECM monitors the duty cycle that is required to actuate the throttle valve. The ECM monitors the throttle position sensors 1 and

2 to determine the actual throttle valve position.

Conditions for Running the DTC

* The vehicle speed is 0 km/h (0 mph).

* The engine speed is less than 40 RPM.

* The engine coolant temperature (ECT) is between 5-100掳C (41-212掳F).

* The intake air temperature (IAT) is between 5-143掳C (41-290掳F).

* The ignition voltage is greater than 10 volts.

* The accelerator pedal position (APP) is less than 15 percent.