P1597

DTC P1597

Circuit Description
The power take off (PTO) accelerator sensor (upfitter installed) detects the PTO control volume angle. The engine control module (ECM) receives the PTO control volume angle from the sensor and controls the fuel injection quantity (engine speed) during PTO. The PTO accelerator has the following circuits.
- 5 volts reference circuit
- Low reference circuit
- PTO accelerator sensor signal circuit

The ECM supplies 5 volts to the PTO accelerator sensor on the 5 volts reference circuit. The ECM also provides a ground on the low reference circuit. The ECM monitors the PTO accelerator sensor signal for voltages outside the normal range of the PTO accelerator sensor. If the ECM detects an excessively high PTO accelerator sensor signal voltage, this DTC will set.

Condition for Running the DTC
- The battery voltage is between 10-16 volts.
- The ignition switch is ON.
- The engine is running.

Condition for Setting the DTC
- The ECM detects that the PTO accelerator sensor signal voltage is more than 4.9 volts.

Action Taken When the DTC Sets
- The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records.
- The ECM inhibits PTO control.

Condition for Clearing the DTC
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- Clear the MIL and the DTC with a scan tool.

Diagnostic Aids
If an intermittent condition is suspected, the following may cause an intermittent:
- Poor connections.
- Misrouted harness.
- Rubbed through wire insulation.
- Broken wire inside the insulation.

Check for the following conditions:
- Poor connection at ECM: Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
- Damaged harness: Inspect the wiring harness for damage. If the harness appears to be OK, observe the "PTO Accelerator Sensor" display on the scan tool with the ignition ON and engine OFF while moving connectors and wiring harness related to the sensor. A change in the display will indicate the location of the fault.

DTC P1597

Schematic Reference: Engine Controls Schematics

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