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Test Description

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

  1. 3:  This step checks for a skewed throttle position (TP) sensor. High resistance in the TP sensor circuit can cause this DTC to set.
  2. 6:  This step tests for the correct operation of the idle switch within the throttle body. The idle switch is a normally closed switch and the test lamp should illuminate with a closed throttle. The test lamp should go OFF when the throttle is opened.
Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connect End View Reference:  Engine Controls Connector End Views 
1 Did you perform the Diagnostic System Check - Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the DTC information with a scan tool.
Is DTC P0122, P0123, P0222 or P0223 also set?		 - Go to Diagnostic Trouble Code (DTC) List Go to Step 3 
3 
  1. Start the engine.
  2. Turn OFF all accessories.
  3. Observe the throttle position (TP) sensor parameter with a scan tool.
Is the TP sensor percentage less than the specified value?		 8 % Go to Step 4  Go to DTC P0122
4 Observe the idle switch parameter with a scan tool while slowly depressing the accelerator pedal to wide open throttle.
Does the idle switch parameter change when the accelerator pedal is depressed?		 - Go to Step 5  Go to Step 6 
5
  1. Observe the Freeze Frame/Failure Records for this DTC.
  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 6  Go to Intermittent Conditions
6 
  1. Turn OFF the ignition.
  2. Disconnect the throttle body harness connector.
  3. Install a jumper wire between the low reference circuit of the ISC motor position sensor harness connector and the low reference circuit of the throttle body.
  4. Connect a test lamp between the signal circuit of the Idle switch at the throttle body and battery voltage.
Does the test lamp illuminate?		 - Go to Step 7  Go to Step 11 
7 Slowly open the throttle to wide open throttle.
Does the test lamp remain illuminated?		 - Go to Step 11  Go to Step 8 
8
  1. Turn ON the ignition, with the engine OFF.
  2. Measure the voltage between the signal circuit of the idle switch and a good ground with a DMM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Is the voltage more than the specified value?		 11 V Go to Step 10  Go to Step 9 
9 Test the idle switch signal circuit for an open or for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 12 
10
IMPORTANT: The throttle body assembly or the engine control module (ECM) may be damaged if the circuit is shorted to a voltage source.
Test the idle switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition?		 - Go to Step 15  Go to Step 12 
11 Test for shorted terminals and for poor connections at the throttle body. 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 15  Go to Step 13 
12 Test for shorted terminals and for poor connections at the engine control module (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 15  Go to Step 14 
13 Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement .
Did you complete the replacement?		 - Go to Step 15  -
14 Replace the ECM. Refer to Engine Control Module Replacement .
Did you complete the replacement?		 - Go to Step 15  -
15
  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.
Did the DTC fail this ignition?		 - Go to Step 2  Go to Step 16 
16 Are there any DTCs that have not been diagnosed? - Go to Diagnostic Trouble Code (DTC) List System OK
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