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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1865 (Engine Controls And Fuel - 3.5L (L66) - DTC P0506 To DTC P2199) >> DTC P1126 >> Test Description

Test Description

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 1:  The Diagnostic System Check-Vehicle prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
  2. 3:  This step checks for a faulty ECT sensor or ECT sensor circuit.
  3. 4:  This step checks the integrity of the ECT sensor signal circuit.
  4. 5:  This step checks the integrity of the ECT sensor signal and ground circuits.
  5. 6:  This step checks the integrity of the ECT sensor ground circuit.
  6. 10:  After replacing the PCM a new minimum throttle position and idle speed must also be established.
  7. 12:  This step determines if DTC P1126 is the result of a hard failure or an intermittent condition.
DTC P1126

Step Action Values Yes No
Connector End View Reference: Powertrain Control Module 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
2 Check for DTC P0117 or DTC P0118 with a scan tool.
Is DTC P0117 or DTC P0118 set?		 - Go to DTC P0117, P0118, P2184, or P2185 Go to Step 3 
3 
  1. Measure the actual coolant temperature.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the ECT sensor parameter on the scan tool.
Is the ECT sensor value displayed near the actual coolant temperature?		 - Go to Step 11  Go to Step 4 
4 
  1. Disconnect the engine coolant temperature (ECT) sensor electrical connector.
  2. Observe the ECT sensor parameter on the scan tool.
Does the engine coolant temperature equal the specified value?		 -40°C (-40°F) Go to Step 5  Go to Step 8 
5 
  1. Jump the ECT sensor signal circuit and the ground circuit together at the ECT sensor harness connector.
  2. Observe the ECT sensor parameter on the scan tool.
Is the engine coolant temperature more than the specified value?		 168°C (334°F) Go to Step 11  Go to Step 6 
6 
  1. Jump the ECT sensor signal circuit to chassis ground.
  2. Observe the ECT sensor parameter on the scan tool.
Is the engine coolant temperature more than the specified value?		 168°C (334°F) Go to Step 7  Go to Step 9 
7 Repair the open or high resistance in the ECT sensor ground circuit. Refer to Wiring Repairs .
Did you complete the repair?		 - Go to Step 15  Go to Step 9 
8
  1. Turn OFF the ignition.
  2. Test the ECT sensor signal circuit for a short.
  3. Repair as necessary. Refer to Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 15  Go to Step 10 
9
  1. Check for a faulty connection at the powertrain control module (PCM) and the ECT electrical connectors.
  2. Repair as necessary.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 10 
10 
  1. Replace the PCM. Refer to Control Module References for replacement, setup, and programming.
  2. Perform the idle learn procedure. Refer to Idle Learn .
Did you complete the replacement?		 - Go to Step 15  -
11 Observe the ECT sensor parameter on the scan tool.
Is the temperature more than 80°C (176°F)?		 - Go to Step 12  Go to Step 13 
12 
  1. Let the engine cool for 1 hour.
  2. Observe the ECT sensor parameter on the scan tool.
Did the ECT sensor parameter indicate that the coolant temperature has decreased more than the specified value?		 2°C (3.6°F) Go to Diagnostic Aids Go to Step 14 
13
  1. Let the engine run at 3,000 RPM until the engine cooling fan turns ON.
  2. Observe the ECT sensor parameter on the scan tool.
Did the ECT sensor parameter indicate that the coolant temperature has increased more than the specified value?		 2°C (3.6°F) Go to Diagnostic Aids Go to Step 14 
14 Replace the ECT sensor. Refer to Engine Coolant Temperature Sensor Replacement .
Did you complete the replacement?		 - Go to Step 15  -
15
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text or until the DTC P1126 diagnostic test has run.
Does the DTC run and pass?		 - Go to Step 16  Go to Step 2 
16 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 System OK
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