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 Descriptors
DTC C0899 03: Device Voltage LowDTC C0900 07: Device Voltage High
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
B+ Voltage Circuit | 1 | 1, C0899 03 | C0900 07 | 1, C0899 03 |
1. Power Take-Off (PTO) Does Not Engage | ||||
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 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 ON.
Conditions for Setting the DTC
| • | The PTO module detects ignition voltage below or above a predetermined voltage threshold. |
| • | Engine speed is greater than 400 RPM. |
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
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
- Ignition ON, verify that DTC P0562, P0563 in the ECM and/or B1325 are not set as current.
- Verify that DTC C0899 or C0900 are current in the scan tool.
| ⇒ | If one of the specified DTCs is found as current, repair those DTCs first. Refer to Diagnostic Trouble Code (DTC) List - Vehicle . |
| ⇒ | If the DTC is not current, refer to Charging System Test . |
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the power take-off (PTO) module.
- Ignition ON, test for greater than 11.0 volts between the B+ voltage circuit terminal 32 and ground.
- Ignition ON, test for greater than 11.0 volts between the B+ voltage circuit terminal 32 and the ground circuit terminal 1.
- Engine ON, test for less than 16 volts between the B+ voltage circuit terminal 32 and ground.
- If all circuits test normal, test or replace the PTO module.
| ⇒ | If less than the specified value, test the B+ voltage circuit for a high resistance. |
| ⇒ | If less than the specified value, test the ground circuit for a high resistance. |
| ⇒ | If greater than the specified value, test the voltage circuit for a short to voltage. If the circuit tests normal, refer to Charging System Test . |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for PTO module replacement, setup, and programming
