P0898 Transmission Control System MIL Request Circuit Low

P0898 indicates the transmission control system MIL request circuit is low. The transmission controller's request path to illuminate the MIL is pulled low or missing.

Code status

Needs verification

Not yet verified against SAE J2012_202509 / J2012DA. Treat unverified rows as a lookup aid, not repair authority.

System: Transmission
Scope: iso-sae-controlled-p0
Standard: SAE J2012 / ISO 15031-6
Source: legacy-import

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not assume there is no transmission fault because the lamp request path itself is faulty.

Useful checks before replacing parts

Scan all modules for transmission, communication, and MIL-request codes to identify the fault behind the lamp request issue.
Check the MIL request circuit or network message path, TCM power and grounds, connector condition, and module communication status.
Verify whether the engine controller receives the transmission fault request and whether the TCM is online when the code sets.

Related OBD-II codes

These nearby transmission entries can help compare wording and fault area. They may share the same verification status as the source database.