Power Take-Off: Overview Chevrolet Silverado 2500

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

1. 2) Lack of communication may be due to a partial or total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
2. 3) The presence of DTCs indicates that the PCM or TAC has detected a fault.
3. 4) The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
4. 5) This step insures that the PTO options in the scan tool are set according to the upfitters recommendations.

Important: The following steps must be completed before using the symptom tables.

1. Perform the «Diagnostic System Check - Power Take-Off (PTO)»(ref-176719-S01527622272005051700000) before using the Symptom Tables in order to verify that all of the following are true: There are no PCM or TAC module DTCs set. The PCM and TAC module can communicate to each other via the serial data links.
2. Review the system operation in order to familiarize yourself with the system functions. Refer to «Power Take-Off (PTO) Description & Operation»(ref-176719-S28964962882005051700000) .

The numbers below refer to the step numbers on the diagnostic table.

1. 2) This step tests Engine Controls and Cruise Control for DTCs.
2. 3) This step tests for open fuses.
3. 4) This step tests the Power Distribution circuits.
4. 5) This step tests the PTO solenoid.
5. 6) This step tests for continuity on the ground circuit.
6. 7) This step tests for voltage at the Battery Positive Voltage and PTO On Switch-Signal circuits.
7. 8) This step tests the PCM and the PTO Engage Signal circuit.
8. 9) This step tests for continuity on the PTO Engage Signal circuit.
9. 10) This step ensures that all of the PCM conditions for engaging the PTO are met.
10. 11) This step tests for ground on the Battery Positive Voltage circuit.
11. 12) This step tests for ground on the Battery Positive Voltage circuit.
12. 13) This step tests for ground on the PTO Supply-Voltage circuit.
13. 14) This step tests for ground on the Ignition 3 Voltage circuit.
14. 17) This step tests for ground on the Power Take-Off Switch Output Enable circuit.
15. 18) This step tests for voltage at the Ignition 3 Voltage circuit.
16. 19) This step tests the PTO Relay.

The numbers below refer to the step numbers on the diagnostic table.

1. 2) This step checks for other system DTCs that may affect the PTO.
2. 6) This step tests the PCM for the PTO Enable signal.
3. 7) This step tests the communication between the PCM and the TAC module.
4. 8) This step tests the PTO On Switch Signal circuit.
5. 9) This step test the PTO On Switch-Signal circuit for an open, high resistance or short to ground.
6. 10) This step tests the Serial Data circuits for an open, high resistance or short to ground.

The number below refers to the step number on the diagnostic table.

1. 4) This step tests the ground circuit.

Scheme 56

1. Remove the I/P cluster bezel. Refer to «BEZEL REPLACEMENT - INSTRUMENT PANEL (I/P) CLUSTER»(ref-176702-S27142492202005051000000) .
2. Pull out the switch housing from the I/P.
3. Disconnect the wire connector to the PTO switch.
4. Remove the PTO switch from the switch housing.