GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Chevrolet T-Series Medium Duty Truck F6/F7/F8 🢒 DTC 🢒 DTC P0512

Conditions for Running

The engine is ON and is idling.

Conditions for Setting the DTC
    • The condition is present for 1.6 seconds.
    • The ECM detects battery voltage on the START input of the ECM.

Action Taken When the DTC Sets

The engine control module (ECM) will illuminate the malfunction indicator lamp (MIL) the first time the fault is detected.

Conditions for Clearing the MIL/DTC

DTC P0512 can be cleared by using the Clear Info option on the Tech 2.

Diagnostic Aids

Inspect for the following conditions:

    • Poor connections at the ECM
        Inspect the harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connections.
    • The relay remains applied on idling during cold start.

DTC P0512 Starter Switch Abnormal

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Electrical Connector End Views

1

Is DTC P0512 set when the ignition is ON or when the engine is operating?

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Go to Step 2

Go to Diagnostic Aids

2
  1. Start the engine and allow it to idle for 30 seconds.
  2. Measure the voltage between the start pin 24 of the ECM and ground.

Does the voltage measure equal to the specified value?

12 V

Go to Step 3

Go to Step 4

3
  1. Inspect the wire harness and/or starter switch for a short to ground or faulty switch.
  2. Repair or replace the wire harness or starter switch as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you complete the action?

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Go to Step 4

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4
  1. Clear the DTCs.
  2. Replace the ECM assembly. Refer to Engine Control Module Replacement/Restore Fuel Rate Data .

Does DTC P0512 reset?

--

Go to Step 2

System OK