GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2009 🢒 Sierra Denali 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 DTC P260A-P260C

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 P260A: Power Take-Off (PTO) Relay Control Circuit

DTC P260B: Power Take-Off (PTO) Relay Control Circuit Low Voltage

DTC P260C: Power Take-Off (PTO) Relay Control Circuit High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

Open or High Resistance

Short to Voltage

Signal Performance

PTO Relay Coil Control Circuit

P260A, P260B

P260B

P260C

P260B

Circuit/System Description

The power take-off (PTO) is an upfitter integrated system that allows the user to create an auxiliary power source. The PTO system specifically controls engine speed to values higher than normal base idle, PTO load relay engagement, and remote starting and shutdown of the engine. When the operator requests PTO using either the PTO switch or PTO remote, the engine RPM will increase to a default standby speed. The engine control module (ECM) converts the data from the engine speed sensor to a 2 pulses/engine revolution signal. When PTO is engaged, the power take-off module (PTOM) sends a GMLAN serial data message to the ECM requesting engine speeds, in accordance with the depressed switches from the PTO switch or remote.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The PTOM detects a fault on the PTO relay coil control circuit that is above or below a predetermined voltage threshold.

Action Taken When the DTC Sets
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The PTOM records the operating conditions at the time the diagnostic fails. The PTOM stores this information in the Failure Records.

Conditions for Clearing the DTC
    • A last test failed, or the current DTC, clears when the diagnostic runs and does not fail.
    • A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic.

Diagnostic Aids

Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.

Reference Information

Schematic Reference

Power Take-Off (PTO) Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Power Take-Off (PTO) Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification
  1. Ignition ON, verify that DTC P0562, P0563 in the ECM and/or B1325 are not set as current.
    2. ⇒If one of the specified DTCs is found as current, repair those DTCs first. Refer to Diagnostic Trouble Code (DTC) List - Vehicle.
  2. Verify that DTC C0899 or C0900 are not current in the scan tool.
    3. ⇒If the any of the specified DTCs are current, repair those DTCs first. Refer to Diagnostic Trouble Code (DTC) List - Vehicle.

Circuit/System Testing
  1. Ignition OFF, disconnect the PTO relay.
  2. Igniton ON, test for 11 volts or greater between the PTO relay supply voltage circuit terminal 86 and ground.
    3. ⇒If less than the specified voltage, test the PTO relay supply voltage circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, disconnect the harness connector at the PTO module.
  4. Ignition ON, test for 0 volts between the PTO relay coil control circuit terminal 28 and ground.
    5. ⇒If greater than the specified value, test the PTO relay control circuit for a short to voltage.
  5. Ignition OFF, connect the PTO relay.
  6. Ignition ON, test for 11 volts or greater between the PTO relay coil control circuit terminal 28 and ground.
    7. ⇒If less than the specified voltage, test the PTO relay coil control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the PTO relay.
  7. If all circuits test normal, replace the PTO module.

Component Testing

PTO Relay

  1. Ignition OFF, disconnect the PTO relay.
  2. Test for 60-180 ohms of resistance between terminals 85 and 86.
    3. ⇒ If the resistance is not within the specified range, replace the relay.
  3. Test for infinite resistance between the following terminals:
    4. • 30 and 86
    • 30 and 87
    • 30 and 85
    • 85 and 87
    ⇒If less than infinite resistance, replace the PTO relay.
  4. Install a 20-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2.0 ohms of resistance between terminals 30 and 87.
    5. ⇒If greater than 2.0 ohms, replace the PTO relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for PTO module replacement, setup, and programming