P0382: Jeep diesel glow-relay circuit B has two fault branches

The 2002 WG 2.7L diesel manual associates P0382 with glow-plug relay 2's control circuit. It documents both an open-circuit subtype and a short-circuit subtype under the same code. The generic glow-plug/heater circuit B title therefore does not identify a single failed glow plug.

Read the subtype and operating state

For the open subtype, the ECM does not detect the expected control-circuit voltage with the ignition on. The short subtype concerns excessive control-circuit current with the ignition off. These different operating states are a reason to retain the complete manufacturer scan description rather than only the five-character code.

The diagnostic sequence commands relay 2 and observes its response, then separates the ASD-fed supply, the relay and the control wiring. An absent feed can make a serviceable relay appear unresponsive. A control wire shorted to voltage, shorted to ground or open presents different evidence and is checked separately.

The factory procedure uses a substitute relay as one controlled comparison; it does not instruct replacing all glow plugs because P0382 is present. If the relay responds during current testing, intermittent connections and the original conditions remain part of the investigation.

Verification and limits

Glow-system electrical tests involve significant current and should follow the vehicle-specific procedure in a qualified workshop. A repair should establish which control-circuit fault existed and confirm operation afterward. This article describes the 2002 WG diesel implementation only; the meaning of circuit B and relay numbering must not be transferred to an unrelated diesel engine.

Source: DaimlerChrysler factory diagnostic procedure, physical PDF pages 92–94. Original archive member: WG/02wged.pdf in the factory-manual download.