P1682 - FAULT CODE - OBD2

P1682 Code failures by brands

P1682 BUICK, CADILLAC, CHEVROLET, GMC, HUMMER, PONTIAC, SATURN: IGNITION 1 SWITCH CIRCUIT 2

Description of DTC code P1682

The ECM (Engine Control Module) has a supply of 2 ignition circuits. The first circuit is provided by the powertrain relay via a fuse. In this circuit 1, power is delivered to all internal circuits of the ECM that are related to the performance of the TAC (Throttle Actuator Control). The second ignition circuit 1 is provided by a crank/operating relay via a fuse and is used to provide power to the internal circuits of the ECM.

When the fault code P1682 OBDII is set, it is because the ECM has found a difference in the voltage levels of both main power inputs to the ECM. An additional code to this one can be stored by referring to the voltage that is different from the other.

Symptoms of fault code P1682

The Check Engine lamp is lit after 3 valid driving cycles have been completed.
It is not possible to start or run the engine.

Causes of OBD2 P1682

The reasons for storing the diagnostic code P1682 OBD2 are:

The power switch may be damaged.
The circuit of the ignition switch may be shorted.
The power relay may be defective.
The Engine Control Module may have deficiencies.

Possible solutions of the DTC code P1682

The steps to solve the DTC code P1682 OBDII are the following:

See the TSB (Technical Service Bulletins).
Check if other DTC codes are set. Diagnose them following the order shown in the scanner.
Check the state of the electrical components related to the power switch. If you discover damage caused by corrosion or wear, make the necessary repairs.
Check the system circuits to make sure that the fuses are not blown. If they are not damaged, it is necessary to check the integrity of the relays. Fix them if necessary.
Check the integrity of the power switch. If you determine that it is faulty, make the appropriate repairs.