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HOMESERVICE MANUALSCHEVROLET2006COBALT SS, 4D SEDAN, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 299 (ENGINE CONTROL SYSTEM - 3.6L (LY7) - DTC P0008 TO DTC P0133)DTC P0125TEST DESCRIPTION
2006 Chevrolet Cobalt SS, 4D Sedan, Standard

Test Description

2006 Chevrolet Cobalt SS, 4D Sedan, StandardSECTION Test Description
WARNING: This page is about a different car, the 2006 Buick LaCrosse and 2006 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers in the diagnostic table.

  1. 3:  This step tests for excess resistance in the ECT circuit.
  2. 4:  This step tests for a skewed sensor through the range of temperatures affecting this DTC.
DTC P0125

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Engine Control Module (ECM) Connector End Views  or  Engine Controls Connector End Views 
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2 Is the engine cooling system low on coolant? - Go to Loss of Coolant in Engine Cooling Go to Step 3 
3  Is the customer's concern that the engine does not reach operating temperature or that the heater output is low? - Go to Thermostat Diagnosis (LY7) in Engine Cooling Go to Step 4 
4 
IMPORTANT: Return to this diagnostic procedure after you complete the thermostat diagnosis.
Test for the correct operation of the thermostat. Refer to Thermostat Diagnosis (LY7) in Engine Cooling.Did you find and correct the condition?		 - Go to Step 13  Go to Step 5 
5
  1. Turn OFF the ignition.
  2. Disconnect the engine coolant temperature (ECT) sensor.
  3. Connect a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the ECT sensor.
  4. Turn ON the ignition, with the engine OFF.
  5. Observe the ECT sensor parameter with a scan tool.
Is the temperature more than the specified value?		 139°C (282°F) Go to Step 9  Go to Step 6 
6
  1. Connect a 3-amp fused jumper between the signal circuit of the ECT sensor and the engine control module (ECM) housing.
  2. Observe the ECT sensor parameter with a scan tool.
Is the temperature more than the specified value?		 139°C (282°F) Go to Step 7  Go to Step 8 
7 Test the low reference circuit of the ECT sensor for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 13  Go to Step 10 
8 Test the signal circuit of the ECT sensor for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 13  Go to Step 10 
9 Test for shorted terminals and poor connections at the ECT sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 13  Go to Step 11 
10 Test for shorted terminals and poor connections at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 13  Go to Step 12 
11 Replace the ECT sensor. Refer to Engine Coolant Temperature (ECT) Sensor Replacement .
Did you complete the replacement?		 - Go to Step 13  -
12 Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming.
Did you complete the replacement?		 - Go to Step 13  -
13
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?		 - Go to Step 2  Go to Step 14 
14 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information System OK
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.