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HOMESERVICE MANUALSCHEVROLET2008CHEVY EXPRESS G2500, VAN CARGO, 6.6 6REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 688 (POWER TAKE-OFF SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESPOWER TAKE-OFF (PTO) DOES NOT ENGAGETEST DESCRIPTION
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6
Test Description
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Test Description
WARNING: This page is about a different car, the 2006 GMC Sierra and 2006 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step tests for an open fog lamp fuse.
- 3: This step tests for open cruise fuse.
- 4: This step tests the battery positive circuit for battery voltage.
- 5: This step tests the battery positive circuit for an open.
- 6: This step tests the PTO relay output circuit for an open.
- 7: This step tests the PTO ON signal circuit for battery voltage.
- 8: This step tests the PTO ON signal circuit for an open.
- 9: This step tests the cruise control set/coast switch signal circuit for battery voltage.
- 10: This step tests the PTO status circuit for an open.
- 11: This step tests the PTO switch and PTO unit ground circuits for an open.
- 12: This step tests the battery positive and PTO relay output circuits for a short to ground.
- 13: This step tests the ignition 3 circuit for a short to ground.
- 14: This step tests the cruise control ON switch signal, cruise control set/coast signal, PTO status, and PTO ON signal circuits for a short to ground.
- 15: This step tests the control side of the PTO relay for proper operation.
Power Take-Off (PTO) Does Not Engage
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Power Take-Off (PTO) Schematics | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | Inspect the fog lamp fuse for an open. Refer to Circuit Protection - Fuses . Is the fuse open? |
Go to Step 12 | Go to Step 3 |
| 3 | Inspect the cruise fuse for an open. Refer to Circuit Protection - Fuses . Is the fuse open? |
Go to Step 13 | Go to Step 4 |
| 4 | Using a DMM, test the battery positive voltage circuit for voltage. Does the DMM indicate battery voltage? |
Go to Step 7 | Go to Step 5 |
| 5 | Using a DMM, test the battery positive circuit for an open or high resistance. Refer to Testing for Continuity and Wiring Repairs . Did you find and correct the condition? |
Go to Step 19 | Go to Step 6 |
| 6 | Using a DMM, test the PTO relay output circuit for an open or high resistance. Refer to Testing for Continuity and Wiring Repairs . Did you find and correct the condition? |
Go to Step 19 | Go to Step 7 |
| 7 |
|
Go to Step 9 | Go to Step 8 |
| 8 | Using a DMM, test the PTO ON signal circuit for an open or high resistance. Refer to Testing for Continuity and Wiring Repairs . Did you find and correct the condition? |
Go to Step 19 | Go to Step 9 |
| 9 |
|
Go to Step 15 | Go to Step 10 |
| 10 | Using a DMM, test the PTO status circuit for an open or high resistance. Refer to Testing for Continuity and Wiring Repairs . Did you find and correct the condition? |
Go to Step 19 | Go to Step 11 |
| 11 | Using a DMM, test the PTO switch and PTO unit ground circuits for an open or high resistance. Refer to Testing for Continuity and Wiring Repairs . Did you find and correct the condition? |
Go to Step 19 | Go to Step 17 |
| 12 | Using a DMM, test the battery positive and PTO relay output circuits for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? |
Go to Step 19 | Go to Step 18 |
| 13 | Using a DMM, test the ignition 3 voltage circuit for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? |
Go to Step 19 | Go to Step 14 |
| 14 | Using a DMM, test the cruise control ON switch signal, cruise control set/coast signal, PTO status, and the PTO ON signal circuit for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? |
Go to Step 19 | Go to Inducing Intermittent Fault Conditions |
| 15 | With the PTO ON, use a fused jumper wire to ground the PTO control circuit. Does the PTO relay turn ON? |
Go to Step 16 | Go to Step 18 |
| 16 | Replace the powertrain control module (PCM). Refer to Control Module References
in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the repair? |
Go to Step 19 | - |
| 17 | Replace the PTO switch. Refer to Power Take-Off (PTO) Switch Replacement . Did you complete the repair? |
Go to Step 19 | - |
| 18 | Replace the PTO relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) . Did you complete the repair? |
Go to Step 19 | - |
| 19 | Operate the PTO system as described in the supporting text. Does the symptom occur? |
Go to Step 2 | System OK |
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.