What does it mean?
P1693 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Malfunction Indication Light Short to B+ .
Symptoms
- The warning lamp never lights, including during the key-on bulb check
- On some circuit layouts the lamp instead stays lit permanently
- Real engine faults go unnoticed because the driver never gets a warning
- Emissions inspection failure for a non-functioning warning lamp
- Other cluster lamps sharing the same connector may also misbehave
- No driveability complaint from the engine itself
Likely causes
- Lamp control wire chafed against a live terminal or shorted to a battery-fed circuit
- Water intrusion into the instrument cluster connector, bridging the lamp pin to a supply pin
- Failed lamp driver inside the control module that can no longer pull the circuit low
- Incorrect wiring after an aftermarket accessory installation or a cluster swap
- Corroded connector pins bridging the lamp circuit to a powered pin
- Harness damage behind the dash from earlier repair work
How to fix it
- Check whether the lamp performs its normal bulb check at key-on and goes out after starting
- Unplug the instrument cluster and measure the lamp circuit for voltage with the ignition on; battery voltage present with the module disconnected confirms the short
- Trace the circuit behind the dash, looking for chafing and previous accessory taps into the harness
- Inspect the cluster connector for corrosion and moisture bridging adjacent pins
- Confirm the correct bulb or LED is fitted where the cluster is serviceable
- Repair the shorted wire and route it clear of powered terminals
- Replace the cluster or the module only if the fault is proven to be internal