Circuit Description
The ignition 1 voltage circuit supplied by the powertrain ignition 1 relay is used to power the electronic throttle control (ETC) circuitry internal to the engine control module (ECM). The second ignition 1 voltage circuit is supplied by the ignition switch through the ECM 1 fuse, and is used to power the remaining internal ECM circuits. If the ECM detects a voltage difference between the two ignition 1 voltage circuits, DTC P1682 will set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1682 Ignition 1 Switch Circuit 2
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The powertrain relay is commanded ON. |
| • | DTC P1682 runs continuously. |
Conditions for Setting the DTC
The ECM detects that the voltage level difference is greater than 3 volts between the ignition switch, ignition 1 voltage circuit and the ETC ignition 1 voltage circuits for more than 3 seconds.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores the information in the Freeze Frame/Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC last test failed clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles if no failures are reported by this or any other emission related diagnostic. |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls 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 | Are DTCs P0615, P0685, P0689, or P0690 also set? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 3 |
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Intermittent Conditions |
4 |
Does the test lamp illuminate on both test points of the ECM fuse? | -- | Go to Step 6 | Go to Step 5 |
5 | Does the test lamp illuminate on one test point of the ECM 1 fuse? | -- | Go to Step 7 | Go to Power Mode Mismatch in Computer/Integrating Systems |
6 |
Does the resistance measure greater than the specified value? | 2ohms | Go to Step 9 | Go to Step 8 |
7 |
Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 8 |
8 | Test for shorted terminals and poor connections at the ECM wire harness electrical connector. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 11 |
9 | Repair the high resistance or an open in the ignition 1 voltage circuit between the underhood fuse block and the ECM. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 12 | -- |
10 | Repair the short to ground in the ignition 1 voltage circuit between the underhood fuse block and the ECM. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 12 | -- |
11 | Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 12 | -- |
12 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 13 |
13 | 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 |
