For 1990-2009 cars

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

1. Perform the Diagnostic System Check - Power Take-Off (PTO) before using the Symptom Tables in order to verify that all of the following are true:

• | There are no powertrain control module (PCM) 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 and Operation .

### Visual/Physical Inspection

• | Inspect the upfitter installed parts and connections of the PTO system. Refer to Checking Aftermarket Accessories in Wiring Systems.

• | Inspect the easily accessible, or the visible system components for obvious damage or conditions which could cause the symptom.

• | Inspect the transmission and the hydraulic pump for the proper fluid level.

### Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

### Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

• | Power Take-Off (PTO) Does Not Engage

• | Engine RPM Does Not Increase with Power Take-Off Engaged

• | Power Take-Off (PTO) Indicator Inoperative