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 engine control relay, through the engine sensor 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 power all the other internal ECM circuits except those, which are used for TAC operation. The ECM continuously monitors both ignition 1 voltage circuits. If the ECM detects a voltage level difference between the 2 circuits,
DTC P1682 will set.
Conditions for Running the DTC
| • | The ignition switch is turned ON. |
| • | The engine control relay has been commanded ON. |
| • | DTC P1682 runs continuously. |
Conditions for Setting the DTC
| • | The voltage level difference is greater 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) on the second consecutive ignition cycle that the diagnostic runs and
fails. |
| • | The control module records the operating conditions at the time
the diagnostic fails. The first time the diagnostic fails, the control module
stores this information in the Failure Records. If the diagnostic reports
a failure on the second consecutive ignition cycle, the control module
records the operating conditions at the time of the failure. The control
module writes the operating conditions to the Freeze Frame and updates
the 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
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. |
| • | If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.
The other option is to refer to
Testing for Intermittent Conditions and Poor Connections
. |
Circuit/System Testing
- If DTCs P0685, P0689, or P0690 are set, test and repair those DTCs first.
- Obtain access to the ignition switch electrical connector.
- With the key OFF, test for battery positive voltage to the ignition switch.
| ⇒ | If less than battery positive voltage test and repair for an open/high resistance, or short to ground, in the voltage supply circuit to the ignition switch. All wire circuit resistance should measure 2 ohms or less. |
- With the ignition ON, perform a voltage drop test across the ignition switch. Measure the amount of voltage drop between the battery positive voltage input terminal/connector, and the ignition 1 voltage output terminal/connector at the ignition switch.
The amount of voltage drop should not exceed 300 millivolts.
| ⇒ | If you measure more than 300 millivolts, inspect and test the ignition switch electrical terminals and mating wire harness electrical connector for corrosion and terminal tightness. |
| ⇒ | If the electrical terminals/connections test normal, replace the ignition switch. |
- With the ignition OFF, disconnect the ignition switch electrical connector that contains the ignition 1 voltage circuit to the ECM. Disconnect the ECM electrical connector that contains the ignition 1 voltage circuit from the ignition switch.
| ⇒ | Test and repair if necessary, the ignition 1 voltage circuit for an open/high resistance, or a short to ground. All circuit resistance should measure 2 ohms or less. |
Component Testing
- Disconnect the ignition switch electrical connectors.
- Remove the ignition switch from the vehicle.
- With the ignition switch turn to the ON position, measure the resistance between the battery positive voltage input terminal, to the ignition 1 voltage output terminal at the ignition switch. Replace the ignition switch if the resistance measure
more than 1 ohm.
Repair Instructions
Important: Always perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Control Module References
for ECM replacement, setup, and programming.
Repair Verification
- Clear the DTCs with a scan tool.
- Turn the ignition OFF for 30 seconds.
- Start the engine. If the engine does not run, go to
Engine Cranks But Does Not Run
.
- If other DTCs are set, go to
Diagnostic System Check - Vehicle
.
