GM Service Manual Online
For 1990-2009 cars only

Object Number: 516923  Size: SF
Engine Controls Components
A/C Pressure Sensor, TP, MAP, ECT and IAT
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The throttle position (TP) sensor circuit provides a voltage signal that changes relative to throttle blade angle. The signal voltage will vary from below 1.0 volt at closed throttle to above 4.0 volts at wide open throttle (WOT). If the Powertrain Control Module (PCM) detects a TP signal voltage that is intermittently less than the range of the TP sensor, DTC P1122 will be set.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The TP sensor intermittently indicates a throttle position signal less than 0.1 volt

Action Taken When the DTC Sets

    • The PCM will not illuminate the malfunction indicator lamp (MIL).
    • The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

    • A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
    • The DTC can be cleared by using the scan tool.

Diagnostic Aids

Inspect for the following conditions:

    • Poor connection at the PCM or sensor--Inspect harness connectors for:
       - Backed out terminals
       - Improper mating
       - Broken locks
       - Improperly formed or damaged terminals
       - Poor terminal to wire connection
    • Use a corresponding mating terminal to test for proper terminal tension.
    • Damaged harness--Inspect the wiring harness for damage. If the harness appears to be OK, observe the TP display on the scan tool while moving connectors and wiring harnesses related to the TP sensor. A change in the display will indicate the location of the malfunction.

If DTC P1122 cannot be duplicated, reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

DTC P1122 - TP Sensor Circuit Intermittent Low Voltage

Step

Action

Values

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Select diagnostic trouble code (DTC) info and note if any other DTCs set.

Is DTC P0122 also set?

--

Go to DTC P0122 Throttle Position (TP) Sensor Circuit Low Voltage

Go to Step 3

3

Is DTC P1107 also set?

--

Go to Step 4

Go to Step 5

4

Test all 5 volt reference A circuits and connected components for an intermittant short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 8

5

Test the 5 volt reference circuit of the TP sensor for an intermittant open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 6

6

Test the signal circuit of the TP sensor for an intermittant short to ground, high resistance, or open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 7

7

Inspect for poor connections at the harness connector of the TP 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 9

Go to Step 8

8

Inspect for poor connections at the harness connector of the PCM. 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 9

Go to Diagnostic Aids

9

  1. Review and record the scan tool Failure Records data.
  2. Clear the DTCs.
  3. Operate the vehicle within the Failure Records conditions as noted.
  4. Using a scan tool, monitor Specific DTC info for DTC P1122.

Does the scan tool indicate DTC P1122 failed?

--

Go to Step 2

System OK