P0898 Transmission Control System MIL Request Circuit Low

The MIL request circuit is a dedicated wire over which the gearbox module asks the engine module to switch on the MIL. Today that request travels over CAN and shows as P0700 in the engine module; older Subarus, also sold as Saab 9-2X, used a single serial wire with its own codes P0864 to P0866. P0898 means the request wire stays at ground: a short to ground or, with active-high logic, a gearbox module without power. The engine module can then not tell a real request from a wiring fault. No maker documents the code; Subaru's P0865 is the closest documented equivalent.

Likely causes

Symptoms

• MIL on
• Gearbox faults may not be indicated correctly

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, static.nhtsa.gov, saabwisonline.com.