P0702: the Jeep diesel engine module is reporting a transmission fault

P0702 in the 2002 WG 2.7L diesel manual is an engine-module report originating from the transmission controller. The factory procedure directs the actual diagnosis to transmission diagnostic information. Treating the engine module's code as a complete component diagnosis discards the more specific evidence stored elsewhere.

Retrieve the transmission's description

The source groups several P0702 messages: ABS sensor information, transfer-case-switch information, improper gear or ratio, internal shifter failure, input-speed sensor circuits and torque-converter-clutch faults. These are substantially different systems. The shared code is not enough to choose a speed sensor, a shifter assembly or an internal transmission repair.

The manual also gives P1242 priority when it accompanies the report. That sequencing should be preserved rather than treating all stored codes as independent replacement instructions. A workshop first establishes which transmission fault is current, then follows that fault's own diagnostic chart.

Clearing one module is not full verification

The procedure uses the ECM record to assess whether the transmission fault report returns, but explicitly requires both ECM and TCM codes to be cleared after repairs are completed. Merely removing the engine-module warning can leave the originating transmission diagnosis unresolved.

A useful service report names the original TCM fault, the supporting checks and the repair verified. If only P0702 was retrieved, the next requirement is access to manufacturer-capable transmission diagnostics, not a speculative parts list. This description is limited to the cited WG diesel control architecture; other manufacturers may use P0702 with different reporting logic.

Source: DaimlerChrysler factory diagnostic procedure, physical PDF pages 161–161. Original archive member: WG/02wged.pdf in the factory-manual download.