GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2007 🢒 TopKick C-Series (Conventional) C6/C7/C8 🢒 Engine 🢒 Engine Controls and Fuel - 7.8L (LF8) 🢒 DTC P1293

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P1293: Injector Circuit Low to High Current Transition Time Bank 1

Circuit/System Description

The charge-up circuit in the engine control module (ECM) steps up the voltage for injectors and is divided into two banks, common 1 and 2. The common 1 covers injectors in cylinders 1 and 4, and the common 2 covers injectors in cylinders 2 and 3.

Conditions for Running the DTC
    • The battery voltage is between 10-16 volts.
    • The ignition switch is ON for longer than 2 seconds.
    • The engine is running.
    • The elapsed time from the starter switch OFF is longer than 2 seconds.
    • The IC watching the CPU in the ECM is normal.
    • The injector drive circuit is normal.

Conditions for Setting the DTC

The ECM detects that the injector charge-up circuit is of insufficient charge or has an overcharge.

Action Taken When the DTC Sets

DTC P1293 is a Type A DTC.

Conditions for Clearing the DTC

DTC P1293 is a Type A DTC.

Diagnostic Aids

Inspect for any recent engine mechanical repairs. An incorrectly installed APP sensor will cause this DTC to set.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Engine Controls Component Views
    •  Engine Control Module Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

Important: If DTCs P0602, P0603, and P062F are set, test and repair those DTCs first.

Verify the integrity of the ECM power supply or ground circuit by inspecting for the following conditions:

    • Damaged components
    • Loose or improper installation

Circuit/System Testing

Important: You must perform Circuit/System Verification before proceeding with Circuit/System Testing.

  1. Test the power supply and ground circuits to the ECM for a short, an open, or high resistance.
  2. Observe the DTCs with the scan tool.
    3. ⇒If DTC P0602 or P062F is set, attempt to program the ECM before replacing the ECM. Refer to Service Programming System (SPS) .
    ⇒If DTC P0606 was set while performing SPS Programming, clear the DTCs and exit the diagnostic.
  3. Replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming