What Does P0898 Mean?
The TCM has detected a low voltage condition on the circuit used to request illumination of the malfunction indicator lamp (MIL) from the instrument cluster. The TCM communicates with the instrument cluster to turn on the check engine light when a transmission fault is detected, and this circuit is not functioning correctly. This may prevent the driver from being alerted to transmission problems.
Common Causes
30%
Short to ground in the MIL request circuit wiring between the TCM and instrument cluster
25%
Corroded or damaged connector at the TCM or instrument cluster for the MIL circuit
20%
Failed instrument cluster MIL driver circuit
15%
Faulty TCM unable to properly drive the MIL request output
10%
Open or high-resistance ground in the MIL request circuit
Diagnostic Steps
1
Verify whether the MIL (check engine light) illuminates during the key-on bulb check; if it does not light at all, the bulb or instrument cluster driver may be faulty.
2
Using a wiring diagram, identify the MIL request circuit between the TCM and instrument cluster and measure voltage at both ends with the key on.
3
Inspect the wiring harness for the MIL request circuit for chafing, pinched wires, or corrosion at connectors.
4
Check if the PCM can independently illuminate the MIL; if so, the issue is isolated to the TCM MIL request path.
5
If wiring tests normal, swap or test the TCM MIL request output by backprobing the connector and commanding the light on via scan tool.
Estimated Repair Cost
$150 - $500
Parts + labor, varies by vehicle and location
The TCM has detected a low voltage condition on the circuit used to request illumination of the malfunction indicator lamp (MIL) from the instrument cluster. The TCM communicates with the instrument cluster to turn on the check engine light when a transmission fault is detected, and this circuit is ...
The most common cause of P0898 (Transmission Control System MIL Request Circuit Low) is: Short to ground in the MIL request circuit wiring between the TCM and instrument cluster
Typical repair costs for P0898 range from $150 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
If the MIL request circuit cannot illuminate the check engine light for transmission faults, the driver may not be warned of serious transmission issues. This could lead to continued operation with an undiagnosed transmission problem.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0898 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission
Difficulty
Type
Generic (SAE)
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