- |P0088 JEEP code description. The Powertrain Control Module provides the Fuel Rail Pressure Sensor with a 5-Volt supply and sensor ground and receives a signal voltage back from the Fuel Rail Pressure Sensor.This sensor signal voltage changes based on the pressure in the fuel rail. The PCM will light the MIL lamp immediately after the diagnostic runs and fails.
- Labor: 1.0. The cost of diagnosing the U0401 JEEP code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
- The P0688 is for the PCM to monitor if the ASD relay is turning on. The ASD relay is in the TIPM and will turn when the PCM wants the Jeep to run. There are two sides to the relay. The load side which takes power from the TIPM, and when relay closes applies that power to fuel injectors, ignition coils.
- The 2012 and up Jeep JK wrangler fan on the 3.6L Pentastar has a few key characteristics: It is an Outrunner motor design. This doesn’t have much bearing on diagnosing problems, but it’s a key difference from the more traditional fan designs in the earlier Jeep JKs. The fan is a 3 wire design, which you can see if you detach the harness.
- P0688: Engine control relay -short to positive: Wiring short to positive, engine control relay, ECM: P0689: ECM/PCM power relay -sense circuit low: Wiring short to earth, ECM/PCM power relay, ECM: P068A: ECM/PCM Power Relay De-Energized Performance - Too Early-P068B: ECM/PCM Power Relay De-Energized Performance - Too Late-P068C