U1989 Diagnostic Trouble Code

U1989 is a kind of OBD-II Diagnostic U-Network Diagnostic Trouble Code.

It is considered generic because it applies to all makes and models of vehicles, although specific repair steps may be different depending on your car model.

Symptoms

Symptoms of a U1989 diagnostic trouble code may include:

Faulty or damaged wiring
The engine oil will exhibit dilution from the ECUs attempts to increase engine temperature. Some vehicles advance the fuel injection timing slightly after top center to afterburn a small amount of fuel to increase exhaust temperatures. Some of this fuel enters the crankcase. When the ECU determines the necessity to regenerate the DPF, the service life of the oil be shortened significantly
Poor fuel economy
Hesitation upon acceleration

Possible Causes :

Some aftermarket accessories and performance modifications
A faulty oxygen sensor. This will set a code in itself, however, a faulty oxygen sensor does not automatically condemn the sensor. The code just means that the sensor signal was not within specifications. An air leak or any of the above will cause an erroneous signal. There is a multitude of O2 codes relating to O2 performance which gives a clue to the problematic area.
A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.

Repair Processes :

Look for missing ground strap or a rusty ground where the fuel tank is grounded to the frame. Check for damage to the wiring harness connector. Pack the connector cavity with dielectric silicone compound (same stuff they use for light bulb sockets and spark plug wires) and reassemble.

Process Tips

Diagnostic trouble code U1989 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.

Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before U1989.

Fortunately, U1989 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U1989 Trouble Code For Specific Cars

U1989 Skoda 430 Keyless Entry Circuit Failure
U1989 Mercedes-benz Ponton Air Suspension Front Height Sensor High (SE) Signal Circuit Failure
U1989 Bmw 118 Calibration Resistor Out Of Range
U1989 Twombly Cyclecar Power Supply #2 Circuit Short to Ground
U1989 Ford Visos Module Transmitted Invalid Data (Non SCP)
U1989 Austin-healey Sport Aux A/C Mode Position Reference Circuit Short to Ground
U1989 Toyota Quantum Park Brake Switch # 2 Applied Circuit Failure