Circuit Description
When the power take-off (PTO) enable switch is turned to the ON position and all PTO engage conditions are met, the engine RPM should increase to the standby speed. Engine RPM is strictly controlled by the engine control module (ECM).
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step checks for other system DTCs that may affect the PTO.
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This step checks for a PTO ON signal to the ECM.
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This step checks the PTO ON signal circuit for an open, short to ground, or high resistance.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Power Take-Off (PTO) Schematics and Cruise Control Schematics | |||
1 | Did you review the Power Take-Off Description and Operation and perform the necessary inspections? | Go to Step 2 | |
Verify the fault is present. Does the system operate normally? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | |
3 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 4 | |
4 | Does the PTO solenoid engage? | Go to Step 5 | |
Does the test lamp light? | Go to Step 7 | Go to Step 6 | |
Test the PTO on switch signal circuit for an open, high resistance or short to ground. Did you find and correct the condition? | Go to Step 9 | Go to Step 8 | |
7 | Replace the Auto Cruise/PTO switch. Did you complete the replacement? | Go to Step 9 | -- |
8 | Replace the ECM. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | Go to Step 9 | -- |
9 | Test drive the vehicle and operate the PTO system as described in the supporting text. Does the symptom occur? | Go to Step 3 | System OK |
