Diagnostic Instructions
DTC Descriptor
DTC P260D: Power Take-Off (PTO) Engaged Indicator Control Circuit
Diagnostic Fault Information
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
| Signal Performance
|
PTO Switch Indicator Control
| P260D
| P260D
| P260D
| P260D
|
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 ignition is ON.
Conditions for Setting the DTC
| • | The PTOM detects an invalid voltage signal at the PTO switch indicator control circuit. |
| • | The above condition is present continuously for greater than a predetermined time threshold. |
Action Taken When the DTC Sets
| • | The ECM stores the DTC information into memory when this diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records. |
| • | PTO becomes disabled until the next ignition cycle. |
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. |
Reference Information
Schematic Reference
Connector End View Reference
Component Connector End Views
Description and Operation
Power Take-Off (PTO) Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Verify that the interior backlighting system operates normal. Refer to
Interior Lighting Systems Description and Operation .
- Engine ON, press 1 on the PTO switch to engage PTO. The PTO LED indicator will turn on blinking at a 0.25 second interval rate when the PTO relay is energized. The indicator turns on solid once the PTO load feedback signal confirms the load
has been engaged or after 3 seconds if load feedback is not utilized by the PTO system.
Circuit/System Testing
Important: If the interior backlighting is malfunctioning, refer to
Interior Backlighting Malfunction before performing this diagnostic.
- Ignition OFF, disconnect the harness connector at the PTO switch.
- Connect a test lamp between LED dimming supply circuit terminal 7 and ground.
- Ignition OFF, turn the headlamps ON and OFF. The test lamp should turn ON and OFF accordingly with the headlamp switch.
| ⇒ | If the test lamp is always ON, test the LED dimming supply circuit for a short to voltage. |
| ⇒ | If the test lamp is always OFF, test the LED dimming supply circuit for a short to ground or an open/high resistance. |
- Ignition ON, verify that a test lamp does not illuminate between the PTO switch indicator control circuit terminal 8 and ground.
| ⇒ | If the test lamp illuminates, test the PTO switch indicator control circuit for a short to voltage. If the circuit tests normal, test or replace the PTO module. |
- Ignition OFF, PTO OFF, verify that a test lamp does not illuminate between the PTO switch indicator control circuit and B+.
| ⇒ | If the test lamp illuminates, test the PTO switch indicator control circuit for a short to ground. If the circuit tests normal, test or replace the PTO module. |
- Ignition OFF, disconnect the harness connector at the PTO module.
- Ignition OFF, test for less than 1.0 ohm of resistance on the PTO switch indicator control circuit between the PTO switch terminal 8 and the PTO module terminal 9.
| ⇒ | If greater than the specified range, test the PTO switch indicator control circuit for an open/high resistance. |
- If all circuits test normal, test or replace the PTO switch.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
