P0514: preserve the Jeep diesel temperature-signal subtype

P0514 is broadly cataloged as battery-temperature circuit range/performance. The 2002 WG 2.7L diesel manual provides two more specific procedures under that code: signal voltage too high and signal voltage too low. The complete scan description determines which branch applies.

The electrical extremes have different causes

The documented high threshold is above 4.9 volts with the ignition on. Its possible causes include an open sensor ground, an open signal path, a signal shorted to voltage and the sensor itself. An open connection can therefore explain a high input without proving that the battery is hot.

The low subtype uses a signal below 0.151 volt. Its investigation considers the sensor, a signal short to ground and a short between signal and sensor ground. Controlled sensor isolation checks whether the input recovers when the sensor is removed from the circuit; continued low voltage redirects attention to wiring or the ECM side.

The high and low tests also use different present-reading criteria at some decision points. Those diagnostic boundaries should not be confused with the monitor thresholds or copied to another calibration.

Interpreting a normal reading today

If the original electrical extreme cannot be reproduced, the manual directs intermittent-condition investigation, including connector and harness condition. A normal battery terminal voltage does not test this temperature-signal path.

After repair, a workshop should confirm a credible temperature input and complete the prescribed diesel verification. The thresholds above belong to this specific 2002 WG diesel source; the generic P0514 title alone does not establish them for other vehicles.

Source: DaimlerChrysler factory diagnostic procedure, physical PDF pages 109–112. Original archive member: WG/02wged.pdf in the factory-manual download.