P1694 - FAULT CODE - OBD2

P1694 BUICK, CADILLAC, CHEVROLET, GMC: TACHOMETER CIRCUIT HIGH VOLTAGE

A tachometer is a device used to take readings of the speed at which the engine shaft rotates, which is why this device is limited by mechanical or electrical instruments. Basically, the tachometer is the one that tells the driver how many revolutions he/she is driving. The tachometer has a needle through which it provides real-time readings, some marks or indicators that indicate certain levels, and a dial.

The location of the tachometer is the dashboard, and its indicator shows the readings resulting from the RPM of the engine shaft. The performance of the tachometer is important for regulating engine operation, although the way they measure speeds varies according to the manufacturer.

DTC P1694 OBD2 is stored when, with the key on, the PCM (Powertrain Control Module) detects voltages in the tachometer circuit that exceed the allowed range.

• Check Engine Lamp illuminated.
• You will not be able to start the engine.
• Problems with the gears.
• Unstable engine.
• Low voltage.

P1694 OBDII diagnostic code is set for one of the following reasons:

• The tachometer circuit wires could be damaged.
• The tachometer may have a short in its circuit due to poor electrical connections.
• The tachometer may be in poor condition.
• Low oil level in the engine.
• Dirty oil.
• Damaged on-board computer.
• PCM error.

To troubleshoot the P1694 OBD2 fault code you must do the following:

• Consult the TSB as a first step.
• Verify that the tachometer circuit has no damage to its cables or connectors. If you discover corrosion or wear in one of these components, make the appropriate repairs.
• Refer to the diagnostic steps to perform voltage tests on the tachometer circuit. The values you obtain in these checks should be compared with those indicated by the manufacturer, and if you detect large differences, make the necessary corrections.