Front Drive Unit Disabled (Dual-Motor Vehicle Running on Rear Motor)
The TESLA-DI_A138 (Tesla Drive Inverter (DI)) EV fault code means: Front Drive Unit Disabled (Dual-Motor Vehicle Running on Rear Motor). This is a serious severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- expert
- Estimated cost
- Depends on the root cause; a drive-unit or inverter fault is diagnosed and quoted by Tesla service. Diagnose the underlying alert before estimating.
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Common Symptoms
- Reduced power and acceleration
- Loss of all-wheel drive on a dual-motor vehicle (rear-drive only)
- A "vehicle needs service" or reduced-power message
- Often accompanied by other drive-inverter alerts that identify the root fault
Probable Causes (Ranked by Likelihood)
- A fault in the front drive unit or front inverter caused the controller to disable the front motor Likely
- A thermal, electrical, or internal drive-inverter condition triggering protective shutdown of the front unit Possible
Step-by-Step Diagnostic Procedure
On a dual-motor car the rear motor keeps the vehicle moving, but you lose AWD traction and full power, so drive cautiously, especially in low-grip conditions.
DI_a138 indicates the front unit was disabled in response to another fault -- read the full alert list to find the root front-drive-inverter cause.
High-voltage drive-unit diagnosis is a Tesla service task.
Frequently Asked Questions
What does DI_a138 mean on a Tesla?
The front drive unit has been disabled. On a dual-motor (AWD) Tesla the car keeps running on the rear motor, but with reduced power and no all-wheel drive. It is triggered by an underlying front-inverter fault.
Can I drive with the front drive unit disabled?
A dual-motor car will still move on the rear motor, so you can drive a short distance, but with reduced power and no AWD traction. Have it diagnosed by Tesla service rather than continuing to drive on it.
Sources
This page is built from documented references. Verify against your own service info before repair work.