Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 3: 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 U0107 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.
- 23: Locating and repairing an individual condition may correct more than one DTC.
DTC U0107
| 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 in Vehicle DTC Information |
| 2 | Is DTC P0604 also set? | - | Go to DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610 | Go to Step 3 |
| 3 |
|
- | Go to Step 4 | Go to Diagnostic Aids |
| 4 | Measure the voltage from the throttle actuator control (TAC) Ignition 1 voltage circuit of the TAC module to a good ground with a DMM. Is the voltage within the specified value? |
B+ | Go to Step 5 | Go to Step 8 |
| 5 |
|
12 V | Go to Step 8 | Go to Step 6 |
| 6 | 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
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 17 |
| 7 | Test the TAC module ignition feed circuit for an open or high resistance with a DMM. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 21 |
| 8 | Test for an open or high resistance in the TAC module ground circuit with a DMM. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 9 |
| 9 | 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
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 10 |
| 10 | Test for a short to voltage at both throttle actuator motor control circuits with a DMM. Refer to Circuit Testing
andWiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 18 |
| 11 | Measure the voltage from the serial data circuits of the TAC module to a good ground with a DMM. Is the voltage within the specified range for both circuits? |
0-4.5 V | Go to Step 12 | Go to Step 14 |
| 12 | Test both serial data circuits at the TAC module 16-way harness connector for continuity to ground with a DMM. Does the DMM indicate the specified value for both circuits? |
O.L. | Go to Step 16 | Go to Step 13 |
| 13 | 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
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 14 |
| 14 | Test for a short between both serial data circuits and all other circuits at the powertrain control module (PCM) and TAC module harness connectors with a DMM. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 15 |
| 15 | 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
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 18 |
| 16 | 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
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 17 |
| 17 | Test for an intermittent and for a poor connections at the TAC module. Refer to Testing for Intermittent Conditions and Poor Connections
and Repairing Connector Terminals
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 19 |
| 18 | Test for an intermittent and for poor connections at the PCM harness connector. Refer to Testing for Intermittent Conditions and Poor Connections
and Repairing Connector Terminals
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 20 |
| 19 | Replace the TAC module. Refer to Throttle Actuator Control (TAC) Module Replacement
. Did you complete the replacement? |
- | Go to Step 22 | - |
| 20 | Replace the PCM. Refer to Control Module References
in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? |
- | Go to Step 22 | - |
| 21 | Replace the Junction Block. Refer to Underhood Electrical Center or Junction Block Replacement
in Wiring Systems. Did you complete the replacement? |
- | Go to Step 22 | - |
| 22 |
|
- | Go to Step 2 | Go to Step 23 |
| 23 | 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 in Vehicle DTC Information | System OK |