Diagnostic Instructions
DTC Descriptor
DTC P253D 00: Power Take-Off (PTO) Relay Feedback Circuit High Voltage
Diagnostic Fault Information
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
| Signal Performance
|
PTO Engage Signal
| 1
| 1
| P253D 00
| 1
|
1. Power Take-Off (PTO) Does Not Increase With Power Take-Off Engaged
|
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 and PTO is engaged.
Conditions for Setting the DTC
| • | The PTOM detects a high voltage signal at the PTO engage signal circuit. |
| • | The above condition is present continuously for greater than a predetermined time threshold. |
Action Taken When the DTC Sets
| • | The PTOM stores the DTC information into memory when this diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | 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 failure is no longer present. |
Reference Information
Schematic Reference
Power Take-Off (PTO) Schematics
Connector End View Reference
Power Take-Off (PTO) Connector End Views
Description and Operation
Power Take-Off (PTO) Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Engine ON, press 1 on the PTO switch to engage PTO. The engine RPM should increase to the default engine speed within a few seconds. Press RES + to increase the engine speed and SET - to decrease the engine speed accordingly.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the PTO module.
- Ignition OFF, disconnect the PTO relay.
- Ignition ON, verify that a test lamp does not illuminate between the PTO engage signal circuit terminal 46 and ground.
| ⇒ | If the test lamp illuminates, test the PTO engage signal circuit for a short to voltage. If the circuit tests normal, test or replace the upfitted remote engine PTO switch assembly. |
- Ignition OFF, connect the harness connector at the PTO module.
- Ignition ON, verify that a test lamp does not illuminate between the PTO engage signal circuit terminal 46 and ground.
| ⇒ | If the test lamp illuminates, replace the PTO module. |
- If all circuits test normal, test or replace the PTO relay.
Component Testing
PTO Relay (If supported by the PTO upfitter wiring)
- Ignition OFF, disconnect the PTO relay.
- Test for approximately 50-200 ohms of resistance between terminals H and J on the upfitter wiring side of the upfitter PTO connector.
| ⇒ | If the resistance is not within the specified range, replace the relay. |
- Test for infinite resistance between the following terminals:
| ⇒ | If less than infinite resistance, replace the PTO relay. |
- Install a 15-amp fused jumper wire between relay terminal J and 12 volts. Install a jumper wire between relay terminal H and ground. Test for less than 2.0 ohms of resistance between the relay switch terminals.
| ⇒ | 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 or TCM replacement, setup, and programming
