GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2002 🢒 GMC C Sierra - 2WD 🢒 Engine 🢒 Engine Controls - 8.1L 🢒 DTC P0700

Circuit Description

The malfunction indicator lamp (MIL) request circuit signals the engine control module (ECM) that the transmission control module (TCM) is requesting MIL illumination.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The TCM is requesting MIL illumination, or that the MIL request circuit is shorted to ground.

Action Taken When the DTC Sets
    • The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

Conditions for Clearing the MIL/DTC
    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Test Description

The number below refers to the step number on the diagnostic table.

  1. If the TCM has DTCs set that are requesting MIL illumination, those DTCs must be diagnosed first.

Step

Action

Values

Yes

No

Schematic References: Automatic Transmission Controls Schematics in Automatic Transmission-Allison

Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Connect a scan tool.

Are there any transmission DTCs set?

--

Go to Step 3

Go to Step 5

3

Diagnose and repair any transmission DTCs. Refer to Diagnostic Trouble Code (DTC) List/Type in Automatic Transmission-Allison.

Did you complete the action?

--

Go to Step 4

--

4
  1. Observe the Freeze Frame/Failure Records data for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running in the DTC or as close to the Freeze Frame/Failure Records data that you observed.

Does the DTC fail this ignition?

--

Go to Step 5

Go to Intermittent Conditions

5
  1. Disconnect the TCM. Refer to Transmission Control Module Replacement in Automatic Transmission-Allison.
  2. Connect a DMM from the MIL request circuit in the TCM harness connector to a good ground.
  3. Turn ON the ignition, with the engine OFF.

Does the voltage measure near the specified value?

B+

Go to Step 7

Go to Step 6

6

Test the MIL request circuit for a 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

7

Replace the TCM. Refer to Transmission Control Module Replacement in Automatic Transmission-Allison.

Did you complete the replacement?

--

Go to Step 9

--

8

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 9

--

9
  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 in the DTC as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step 10

Go to Step 2

10

Observe the stored information, Capture Info with a scan tool.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK