• | 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. |
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 |
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.
The engine is ON.
• | The PTO module detects ignition voltage below or above a predetermined voltage threshold. |
• | Engine speed is greater than 400 RPM. |
• | 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. |
• | 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. |
Power Take-Off (PTO) Schematics
Power Take-Off (PTO) Connector End Views
Power Take-Off (PTO) Description and Operation
⇒ | 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 . |
⇒ | 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 . |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for PTO module replacement, setup, and programming