OBD Guide

P0899

Transmission Control System MIL Request Circuit High

P0899 is an OBD-II diagnostic trouble code meaning: Transmission Control System MIL Request Circuit High. Common causes: short circuit in mil request circuit, broken wiring. Estimated repair cost: $17–111.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–111 (est.)

Symptoms

  • Check Engine Light Is On
  • The transmission goes into emergency mode
  • Limited gear shift
  • Reduced engine power
  • Possible problems with cruise control

Causes

  • Short circuit in MIL request circuit
  • Broken wiring
  • Transmission control module (TCM) malfunction
  • Relay or fuse problems
  • Corrosion of contacts in connectors

How to Fix

  1. Check wiring continuity in MIL request circuit
  2. Inspect TCM connectors for corrosion or damage.
  3. Check MIL Request Circuit Voltage
  4. Test or replace TCM if necessary
  5. Check and replace damaged relays or fuses

Related codes

Error P0899 by Vehicle Brand

FAQ

What does the P0899 code mean?

P0899 is an OBD-II diagnostic trouble code that indicates: Transmission Control System MIL Request Circuit High

What causes a P0899 error code?

The most common causes of P0899 include: Short circuit in MIL request circuit; Broken wiring; Transmission control module (TCM) malfunction; Relay or fuse problems.

How do I fix a P0899 diagnostic trouble code?

To fix P0899: Check wiring continuity in MIL request circuit. Inspect TCM connectors for corrosion or damage.. Check MIL Request Circuit Voltage. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0899?

Yes, but get it checked soon

How much does it cost to fix P0899?

The estimated repair cost for P0899 is $17–111. Actual cost depends on your vehicle, location, and labor rates.

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