GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2002 🢒 Tracker - 2WD 🢒 Engine 🢒 Engine Controls - 2.5L (LE8) 🢒 DTC C1215

Circuit Description

The EBCM uses the Powertrain Control Module (PCM) to increase the engine idle speed during certain ABS events, especially those on icy road conditions. The EBCM is connected to the PCM through the Idle Up circuit. When deemed necessary, the EBCM grounds this circuit which signals the PCM to increase idle speed from 850 RPM to 1500-2000 RPM. If an open or short to voltage occurs in the Idle Up circuit, the EBCM will be unable to request the PCM to increase engine speed.

If a short to ground occurs in the Idle Up circuit, the PCM will increase the engine idle speed continuously, once the vehicle speed has reached at least 20 km/h (12 mph).

Conditions for Running the DTC

The DTC can be set anytime after initialization.

Conditions for Setting the DTC

This DTC will set when the following conditions are met:

    • The EBCM detects an open or short to ground in the Idle Up circuit.
    • The EBCM can detect a short to voltage in the Idle Up circuit only during the time that the EBCM is requesting the PCM to idle-up.

Action Taken When the DTC Sets
    • A malfunction DTC stores.
    • ABS remains functional.

Conditions for Clearing the DTC
    • The condition responsible for setting the DTC no longer exists and the Scan Tool Clear DTCs function is used.
    • 100 drive cycles pass with no DTCs detected. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition OFF.

Diagnostic Aids

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:

    • A short to ground or a short to voltage in the Idle Up circuit.
    • An open or high resistance in the Idle Up circuit.
    • An internal EBCM malfunction.

If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Step

Action

Value(s)

Yes

No

Schematic Reference: Antilock Brake System Schematics

1

Did you perform A Diagnostic System Check - ABS?

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Go to Step 2

Go to Diagnostic System Check - ABS

2
  1. Turn OFF the ignition.
  2. Disconnect EBCM connector.
  3. Disconnect the Idle-Up circuit PCM connector.
  4. Connect the J 39700 pinout box with the J 39700-99 pinout box cable adapter to the EBCM harness connector only.
  5. Test the Idle Up circuit for an open, short to ground, or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 7

Go to Step 3

3
  1. Turn OFF the ignition.
  2. Reconnect the EBCM connector.
  3. Reconnect the Idle-Up circuit PCM connector.
  4. Raise and suitably support vehicle. Refer to Lifting and Jacking the Vehicle in General Information. Make sure driving wheels are off the ground as they will rotate during the test.
  5. Install a scan tool and select Idle Up Test.
  6. Start and warm up engine to normal operating temperature (this test will not work if the engine is cold).
  7. Accelerate driving wheels to 25 km/h (15 mph) and maintain speed.
  8. Release accelerator, let engine return to idle speed (while transmission is still in gear), then quickly command ON the Idle Up Circuit with the scan tool.

    9. Note: If the speed of the driving wheels drop below 25 km/h (15 mph) while commanding ON the Idle-Up Circuit, the PCM will ignore and requests to idle-up from the EBCM. This is a normal condition. Repeat Step 7 above if needed.

  9. Press the brake pedal to stop driving the wheels, and turn the engine OFF.

Does the engine idle speed increase to the specified value when the Idle Up Circuit is commanded ON?

1500 - 2000 RPM

Go to Diagnostic Aids

Go to Step 4

4
  1. Turn OFF the ignition.
  2. Connect the J 39700 with the J 39700-99 to the EBCM harness connector only.
  3. Connect a DMM between ground and the Idle-Up Signal circuit of the J 39700 .
  4. Turn the ignition switch to ON.
  5. Command the Idle Up Circuit ON with the scan tool while measuring the voltage on the DMM.

Is the voltage measured within the specified range when the Idle Up Circuit is commanded ON?

0-1 V

Go to Step 5

Go to Step 6

5

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls.

Did you complete the replacement?

--

Go to Step 7

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6

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Did you complete the replacement?

--

Go to Step 7

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7
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

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Go to Step 2

System OK