GM Service Manual Online
For 1990-2009 cars only

Object Number: 402824  Size: SF
OBD II Symbol Description Notice
Engine Controls Components
Cell 21: Engine Data Sensors-A/C Refrig Press, TP, MAP, ECT, IAT
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 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

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

Action Taken When the DTC Sets

The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.

Conditions for Clearing the MIL/DTC

    • The DTC becomes history when the conditions for setting the DTC are no longer present.
    • The history DTC clears after 40 malfunction free warm-up cycles.
    • The PCM receives a clear code command from the scan tool.

Diagnostic Aids

Check 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, and poor terminal to wire connection. Use a corresponding mating terminal to test for proper tension.
    • Damaged harness.
        Inspect the wiring harness for damage. If the harness appears to be OK, observe the throttle position 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 Fail 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

Value(s)

Yes

No

1

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

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Select 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 Wiring Repairs .

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 Wiring Repairs .

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 Wiring Repairs .

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 Intermittents and Poor Connections Diagnosis and Connector Repairs .

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 Intermittents and Poor Connections Diagnosis and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 9

Go to Diagnostic Aids

9

  1. Review and record scan tool Fail Records data.
  2. Clear DTCs.
  3. Operate the vehicle within Fail 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