Gearbox & TCM Repair
Transmission control units and mechatronic modules cause limp mode, harsh or missing gears and lost communication. Before any repair we check whether the fault is electronic or mechanical, so you do not pay for a module that is not the cause.
- Original unit repaired & returned
- Tested before and after repair
- Written test report
- Free tracked UK return
- No VAT added
Common symptoms
- Gearbox in limp mode or stuck in one gear
- Harsh, delayed or missing gear changes
- Transmission control fault codes such as P0700, P0613
- No communication with the TCM
Before you send the unit
- Note the part number from the label and take a clear photo of it
- Read and write down all fault codes, including those in other modules
- Check wiring, fuses and supply first, so you know the module is the likely cause
- Pack it using our packing instructions
Gearbox and transmission control modules
Gearbox warnings, communication problems and shifting faults can involve the TCM, wiring, power supply or mechanical and hydraulic components. Send the part number, gearbox and vehicle details, symptoms and fault codes so we can confirm whether we can assess your unit.
Assessment starts from £45 per module. We confirm the scope, price and delivery arrangements before booking. The assessment fee is credited against an approved repair for the same unit. No repair starts without your approval. See how it works.
What the assessment includes and how payment works · Request an assessment
Bench test and written repair quote: £45 per module (£80 for the JLR 48V DC/DC converter). The fee is deducted from the repair if you approve it. If you decline, no fault is found or the unit cannot be repaired, you pay only the test fee and we return the unit with the report – tracked UK return is included. No repair starts without your approval. See how it works.
Common symptoms of faulty gearbox control units (TCM / mechatronic)
- Gearbox stuck in one gear or limp mode
- Harsh, delayed or erratic shifting
- Gear indicator flashing or missing
- No communication with the TCM
Typical fault codes
| P0700 | Transmission control system malfunction |
| P0613 | TCM processor fault |
| P0715 | Input/turbine speed sensor circuit |
| U0101 | Lost communication with TCM |
Codes vary by manufacturer. Send us your full fault code readout with the part number.
Possible causes
- Internal speed sensor or solenoid circuit fault
- Overheating or oil contamination in mechatronic units
- Connector or wiring damage
- Software or adaptation issues after replacement
How we check it
Mechanical gearbox wear can show the same symptoms. We advise a fluid and mechanical check where relevant. Each unit is assessed individually; any repair starts only after you approve the quotation. Repair prices are quoted individually after the agreed assessment.
Send your unit
Request a quote with your vehicle registration, part number and fault codes. Start a repair request →
How the repair works
Order the repair by part number, or send a repair request if you are unsure.
Post it with tracking or book our courier collection. You get a TTR job number.
We test the unit and confirm the fault. Extra work is quoted first.
The faulty circuit is repaired and the unit is tested again with the same checks.
You get a written result and the unit back by tracked delivery.
Repairs in this category
Repair from £165.00Assessment only — £45.00
Assessment fee deducted from an approved repair. Repair is not included in the assessment price.Gearbox Control Unit (TCM) Repair
Repair from £350.00Assessment only — £45.00
Assessment fee deducted from an approved repair. Repair is not included in the assessment price.
Questions about Gearbox & TCM Repair
Can my original unit be repaired instead of replaced?
In many cases yes. We test your own unit on the bench, find the faulty circuit and repair it. Because it is your original unit, it usually keeps its coding and vehicle data. If it cannot be repaired, we tell you before any further work.
What if the unit turns out to be unrepairable?
You pay only the bench test fee shown on the repair page, and the unit is returned to you. Any extra work beyond the ordered repair is quoted first and done only with your approval.
How do I know the repair was successful?
Every unit is checked before and after repair with the tests available for that module type. The report states the result (pass, partial or fail), what was tested and what could not be tested on the bench.
Do I need coding or calibration after fitting?
An original unit normally goes back without coding. Some systems need a basic setting or calibration in the vehicle after refitting; where this applies, it is stated on the repair page and in the report.
How do I follow my repair?
Each job gets a TTR number and its own status page, updated as the unit moves from receipt to diagnosis, repair and return.