Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step determines if the ignition relay is supplying a voltage to the ETC fuse.
- 5: Increasing the engine speed to 3,000 RPM aids in locating a shorted throttle actuator motor control circuit. Depending on the polarity of the throttle actuator motor transistors, this DTC may not set with a fault in the control circuits. The throttle actuator motor is a bi-directional DC motor. Raising the engine speed changes the polarity of the transistors in the throttle actuator motor. This occurs because one set of the transistors is low, 0 volts, and the other set is high, B+. Therefore, if one set of transistors is at a low voltage and the corresponding circuit is shorted low, DTC P1518 will not set. When the polarity of the transistors change, this DTC sets. If this DTC does not fail this ignition, continue to monitor this DTC status while moving related harnesses and connectors.
- 29: Locating and repairing an individual condition may correct more than one DTC.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle | |
| 2 | Turn ON the ignition, with the engine OFF. Remove the cover from the underhood electrical center. Test both sides of the electronic temperature control (ETC) fuse with a test lamp connected to ground. Does the test lamp illuminate on at least one side of the fuse? | Go to Step 3 | Go to Ignition Relay Diagnosis | |
| 3 | Turn OFF the ignition Test for voltage at the ETC fuse with a test lamp connected to ground. Does the test lamp illuminate? | Go to Step 22 | Go to Step 4 | |
| 4 | Connect a scan tool. Is DTC P0604 also set? | Go to DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610 | Go to Step 5 | |
| 5 | IMPORTANT: If the driver information center is displaying Reduced Engine Power, go to Step 6. Start the engine. Increase the engine speed to 3,000 RPM, if possible. Monitor the DTC Info option using the scan tool. Does the scan tool indicate this DTC failed this ignition? | Go to Step 6 | Go to Diagnostic Aids | |
| 6 | Turn OFF the ignition. Disconnect the throttle actuator motor harness connector. Turn ON the ignition, with the engine OFF. Test for voltage at both throttle actuator motor control circuits with a DMM. Does the DMM indicate voltage on both circuits above the specified value? | 1 V | Go to Step 12 | Go to Step 7 |
| 7 | Turn OFF the ignition. Disconnect the throttle actuator control (TAC) module connectors. Test both throttle actuator motor control circuits for continuity to ground with a DMM. Does the DMM indicate continuity to ground? | Go to Step 10 | Go to Step 8 | |
| 8 | Turn OFF the ignition. Remove the ETC fuse. Test the TAC side of the fuse terminal for continuity to ground with a DMM. Refer to Diagnostic Aids for terminal identification table. Does the DMM indicate continuity to ground? | Go to Step 9 | Go to Step 11 | |
| 9 | Disconnect the TAC module 16-way harness connector. Test the TAC side of the fuse terminal for a short to ground with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 28 | Go to Step 24 | |
| 10 | Disconnect the TAC module 16-way harness connector. Test the throttle actuator motor control circuits for a short to ground at the TAC module 16-way harness connector with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 28 | Go to Step 24 | |
| 11 | Turn OFF the ignition. Disconnect the TAC module 16-way harness connector. Test the TAC module ignition feed circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 28 | Go to Step 24 | |
| 12 | Turn OFF the ignition. Disconnect the TAC module 16-way connector. Turn ON the ignition, with the engine OFF. Test for a short to voltage at both throttle actuator motor control circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 28 | Go to Step 13 | |
| 13 | Turn OFF the ignition. Disconnect the TAC module 10-way harness connector. Test for a short between each throttle actuator motor control circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 28 | Go to Step 14 | |
| 14 | Test for an open or high resistance in the TAC module ground circuit with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 28 | Go to Step 15 | |
| 15 | Test for voltage on the serial data circuits at the TAC module 16-way harness connector with a DMM. Does the DMM indicate voltage within the specified values for both circuits? | 0-4.5 V | Go to Step 16 | Go to Step 18 |
| 16 | Turn OFF the ignition. Test both serial data circuits at the TAC module 16-way harness connector for continuity to ground with a DMM. Does the DMM indicate OL for both circuits? | Go to Step 20 | Go to Step 17 | |
| 17 | Disconnect the powertrain control module (PCM) connector containing the TAC module serial data circuits. Test both serial data circuits at the TAC module 16-way connector for a short to ground with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 28 | Go to Step 18 | |
| 18 | Test for a short between both serial data circuits and all other circuits at the PCM and TAC module harness connectors with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 28 | Go to Step 19 | |
| 19 | Test for a short to voltage on both serial data circuits at the TAC module 16-way connector with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 28 | Go to Step 25 | |
| 20 | Disconnect the PCM connector that contains the TAC module serial data circuits. Test each serial data circuit between the TAC module 16-way harness connector and the PCM harness connector for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 28 | Go to Step 21 | |
| 21 | Connect the PCM. Turn ON the ignition. Test for voltage on the serial data circuit at the TAC module 16-way harness connector with a DMM. Does the DMM indicate voltage at the specified value? | 0 V | Go to Step 25 | Go to Step 24 |
| 22 | Turn OFF the ignition. Disconnect the 16-way TAC module harness connector. Test the TAC module ignition feed circuit for a short to battery voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 28 | Go to Step 23 | |
| 23 | Turn ON the ignition. Test both TAC motor circuits for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 28 | Go to Step 24 | |
| 24 | Test for poor connections at the TAC module harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition? | Go to Step 28 | Go to Step 26 | |
| 25 | Test for poor connections at the PCM harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition? | Go to Step 28 | Go to Step 27 | |
| 26 | Replace the TAC module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 28 | ||
| 27 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 28 | ||
| 28 | Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 29 | |
| 29 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK | |
| IMPORTANT |
|---|
| If the driver information center is displaying Reduced Engine Power, go to Step 6. |
DTC U0107