GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2004 🢒 Wave 🢒 DTC 🢒 DTC P1114

Circuit Description

The engine coolant temperature sensor (ECT) is a thermistor mounted in the engine coolant stream. The engine control module (ECM) applies 5-volt reference voltage through a pull-up resistor to the ECT signal circuit. When the engine coolant is cold, the sensor resistance is high, and the ECM will monitor a high signal voltage. As the engine coolant warms, the sensor resistance is less, and the ECT signal voltage measured at the ECM drops. With a fully warmed engine, the ECT signal voltage should measure about 1.5-2 volts. If the ECM detects an ECT signal that is intermittently below the range of the ECT sensor, DTC P1114 will set.

Conditions for Setting the DTC
    • The ECT is greater than 149°C (300°F).
    • The engine has been running for over 60 seconds.

Action Taken When the DTC Sets
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The ECM 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.
    • A history DTC is stored.

Conditions for Clearing the MIL/DTC
    • A history DTC will clear after 40 consecutive warm-up cycles without a fault.
    • DTCs can be cleared by using the scan tool.
    • Disconnect the ECM battery feed for more than 10 seconds.

Diagnostic Aids

Inspect for the following conditions:

    • A poor connection at the ECM--Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and a poor terminal-to-wire connection.
    • A damaged harness--Inspect the wiring harness for damage. If the harness appears to be OK, observe the ECT display on the scan tool while moving connectors and wiring harnesses related to the ECT sensor. A change in the ECT display will indicate the location of the fault.
    • 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.
    • Use the Temperature vs. Resistance Values table to evaluate the possibility of a skewed sensor. Refer to Temperature Versus Resistance .

Test Description

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

  1. The On-Board Diagnostic System Check prompts the technician to complete some basic checks and store the Freeze Frame and Failure Records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.

Step

Action

Yes

No

1

Perform an On-Board Diagnostic System Check.

Was the check performed?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Install a scan tool to the data link connector (DLC).
  2. Turn the ignition ON.
  3. Request the engine DTC.

Is DTC P0117 also set?

Go to applicable DTC table

Go to Step 3

3

Inspect the engine coolant temperature (ECT) signal circuit between terminal 1 of the ECT sensor and terminal A11 of the engine control module (ECM) for an intermittent short to ground and repair as needed.

Did you find and correct the condition?

Go to Step 4

Go to Diagnostic Aids

4
  1. Using the scan tool, clear the DTCs.
  2. Start the engine and idle at normal operating temperature.
  3. Operate the vehicle within the Conditions for Setting the DTC as specified in the supporting text.

Does the scan tool indicate that this diagnostic has run and passed?

Go to Step 5

Go to Step 2

5

Are any DTCs displayed that have not been diagnosed?

Go to applicable DTC table

System OK