LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Buick >> 2007 >> Allure CXS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - 3.6L - DTC P0008 To P0133 >> DTC P0122 >> Test Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test Description

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

  1. 2:  This step verifies that a condition exists.
  2. 4:  The TP sensors share a 5-volt reference circuit. If both DTCs P0122 and P0222 set, test for a condition in the 5-volt reference circuit.
  3. 5:  This step tests for a condition in the 5-volt reference circuit of the TP sensor. If the DMM displays less 4.8 volts test for a high resistance, an open, or a short to ground in the circuit.
  4. 6:  This step tests the signal 1 circuit of the TP sensor. If the TP sensor 1 voltage parameter is not 4.8-5.2 volts, test for a condition in the signal 1 circuit.
DTC P0122

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Engine 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 in Vehicle DTC Information
2 
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the TP sensor 1 voltage parameter with a scan tool.
Is the voltage less than the specified value?		 0.18 V Go to Step 4  Go to Step 3 
3
  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 4  Go to Diagnostic Aids
4  Observe the DTC information with a scan tool.
Did DTC P0222 also set?		 - Go to Step 5  Go to Step 6 
5 
  1. Turn OFF the ignition.
    2. NOTE: Refer to Disengaging Connectors Notice .
  2. Disconnect the throttle body harness connector. Refer to Throttle Body Assembly Replacement .
  3. Turn ON the ignition, with the engine OFF.
    4. NOTE: Do NOT use the low reference circuit in the component harness connector for this test. Damage to the control module may occur due to excessive current draw.
    IMPORTANT: Use the J 35616-200  Test Lamp Kit for this test. See Special Tools . If the J 35616-200  is not available, use a test lamp that measures more than 20 ohms. See Special Tools .
  4. Connect a test lamp between the 5-volt reference circuit of the throttle position (TP) sensor and the engine control module (ECM) housing.
  5. Connect a DMM to the probe of the test lamp and the ECM housing. Refer to Measuring Voltage Drop in Wiring Systems.
Is the voltage less than the specified value?		 4.8 V Go to Step 7  Go to Step 9 
6 
  1. Turn OFF the ignition.
    2. NOTE: Refer to Disengaging Connectors Notice .
  2. Disconnect the throttle body harness connector. Refer to Throttle Body Assembly Replacement .
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the TP sensor and the signal 1 circuit of the TP sensor.
  5. Observe the TP sensor 1 voltage parameter with a scan tool.
Is the voltage within the specified range?		 4.8-5.2 V Go to Step 9  Go to Step 8 
7
IMPORTANT: The engine control module (ECM) for this engine is not equipped with 5-volt reference DTCs. The 5-volt reference circuits are internally and externally connected at the controller. Other sensors that share the 5-volt reference circuit may also have DTCs set. Disconnecting a sensor on the shared 5-volt reference circuit may isolate a shorted sensor. Review the electrical schematic and diagnose the shared circuits and sensors.
Test the 5-volt reference circuit of the TP sensor and all shared 5-volt reference circuits for the following:
  • An open
  • A short to ground
  • 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 1 circuit of the TP sensor for the following:
  • A short to ground
  • An open
  • 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 an intermittent and for a poor connection at the throttle body assembly. 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 an intermittent and for a poor connection 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 throttle body assembly. Refer to Throttle Body Assembly 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
scientia non olet · About LEMON Manuals