DTC Descriptor
DTC P1682: Ignition 1 Switch Circuit 2
Diagnostic Fault Information
Important: Always perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
| Signal Performance
|
Ignition 1 Switch Circuit 2
| P1682
| P1682
| --
| --
|
Circuit/System Description
There are 2 ignition 1 voltage circuits supplied to the engine control module (ECM). The first ignition 1 voltage circuit is provided by the powertrain relay, through the TAC fuse, located in the underhood fuse block. This ignition 1
voltage circuit supplies power to all the internal ECM circuits associated with the throttle actuator control (TAC) operation, and to both TAC motor control circuits to the throttle body. The ignition switch provides the second ignition 1 voltage circuit
to the ECM, through the ECM 1 fuse located in the underhood fuse block. This ignition 1 voltage provides power to all internal ECM circuits, except those associated with TAC operation. The ECM continuously monitors both ignition 1 voltage
circuits. If the ECM detects a voltage level difference between the two circuits, DTC P1682 will set.
Conditions for Running the DTC
| • | The ignition switch is turned ON. |
| • | The powertrain relay has been commanded ON. |
| • | DTC P1682 runs continuously. |
Conditions for Setting the DTC
| • | The voltage level difference is more than 3 volts between the 2 ignition 1 voltage circuits to the ECM. |
| • | The condition is present 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 this information in the Freeze
Frame/Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (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. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
| • | This test procedure requires that the vehicle battery has passed a load test and is completely charged. |
| • | When disconnecting electrical connectors or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion , and the mating electrical terminals for tightness. |
| • | Use the
J 35616
Connector Test Adapter Kit for any test that requires probing the underhood fuse block terminals, component wire harness terminals, or the ECM wire harness connector terminals. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Special Tools Required
J 35616
Connector Test Adapter Kit
Circuit/System Verification
With the key ON, engine OFF, monitor the ignition 1 signal parameter with a scan tool. The ignition 1 signal parameter should display battery voltage.
Circuit/System Testing
| • | If DTC P0685, P0689, or P0690 are set, test and repair those DTCs first. |
| • | With the ignition ON, and the engine OFF, test for ignition 1 voltage at both test points of the ECM 1 fuse in the underhood fuse block. |
| ⇒ | If the ignition 1 voltage is not present on either test point of the ECM 1 fuse, then replace underhood fuse block. |
| ⇒ | If the ignition 1 voltage is present on one test point of the ECM 1 fuse, then repair the short to ground in the ignition 1 voltage circuit to the electronic control module (ECM). If the wire circuit tests normal, then replace
the ECM. |
| ⇒ | If the ignition 1 voltage is present on both test points of the ECM 1 fuse, then inspect and test for loose and corroded terminals at the underhood fuse block electrical connector, and the ECM electrical connectors, which contains the
ignition 1 voltage circuit. If the electrical connectors test normal, then repair the ignition 1 voltage circuit, for an open or high resistance. All wire circuit resistance should measure 2 ohms or less. If the wire circuit tests normal,
refer to
Powertrain Relay Diagnosis
. |
Repair Instructions
Important: Always perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
