EV Hybrid Service/Services
Electric motor and hybrid transmission repair
On a hybrid, “the engine” often means the electric motors and the hybrid transmission, not just the petrol engine. When noises, vibrations or loss of power appear, we look for the cause by measurement and on the road, before talking about major dismantling.
When the motor and transmission need checking
It is worth coming in when the noise, vibration or loss of power seems linked to the hybrid side: the electric motors, the transmission, the bearings or the damper between engine and transmission. We start with diagnostics and dismantle only when the measurements call for it.
A metallic noise or hum when accelerating or braking
A noise that rises with road speed rather than with petrol engine revs can come from bearings in the transmission or from the electric motors. We locate it by the type of sound, speed and load, not by replacing everything.
Vibrations when the petrol engine starts or stops
Jolts or vibrations as the petrol engine starts can come from the engine mounts, the damper between engine and transmission, or the engine itself. A road test separates them.
Loss of power with no clear battery faults
The car no longer pulls, even though the battery looks fine. The inverter, electric motors or transmission can limit power. Reading the codes and a load test show us the cause.
Misfires or knocking from the petrol engine
On some hybrids, such as the third-generation Prius, the exhaust gas recirculation (EGR) circuit clogs with carbon and oil, and the engine starts to misfire and knock. It needs sorting out in time, before it affects the head gasket.
Why a hybrid isn’t repaired like a conventional engine
Rebuilding the petrol engine won’t fix a worn electric motor or a broken bearing in the transmission. On a hybrid, the expensive part is often the electric side and the transmission, which is why we measure before taking anything apart.
MG1 and MG2 are the heart of the hybrid
In Toyota’s hybrid transmission, MG1 splits the petrol engine’s power and also starts it, while MG2 drives the car, recovers energy under braking and handles reversing on its own. A noise from around them must be located precisely; a wrong diagnosis means needless dismantling.
The hybrid transmission has no gears to shift
Toyota’s hybrid transmission (e-CVT) has no conventional gearbox, clutch or belt. The ratio changes electronically, through the speeds of the two electric motors. That is why its symptoms read differently from an automatic gearbox.
We tell you up front what is realistic
Some jobs need major dismantling or parts that are hard to find. We tell you what can be done on your model before starting the work.
How we work, step by step
We listen to the symptom, read the codes, road-test, separate the electric motors from the transmission, petrol engine and inverter, then suggest a repair for the confirmed cause.
1. You tell us when the problem appears
Cold or warm, under acceleration, braking or at a steady speed. From that we decide what to listen for and what to measure first.
2. We read the codes and look the car over
We read the codes from the electric motors, transmission, inverter and related systems. We check for leaks, the mounts and signs of earlier work.
3. Road test and locating the problem
We reproduce the noise or loss of power. As far as possible, we separate the electric motors, transmission, petrol engine and inverter based on behaviour and live data.
4. We repair the confirmed cause
We repair or replace what we have confirmed. If major dismantling is needed, we explain beforehand what it involves and what the risks are.
5. Final test and handover
We road-test the car, check the codes and explain what we measured, what we replaced and what limits remain.
What motor and transmission work includes
The final quote comes after diagnosis. As a rule, the check includes:
- Diagnosis of the hybrid system, electric motors and transmission
- Reading and interpreting electric motor and transmission codes
- Visual inspection of mounts, leaks and vulnerable areas
- A road test to locate the noise, vibration or loss of power
- Separating the causes: electric motors, transmission, petrol engine, inverter
- Checking live data under load, where relevant
- Repairing the confirmed cause and a final test
- An explanation on handover and a warranty on the work
What we often find
We will publish real, documented jobs one by one. Until then, here are situations we come across often:
Toyota / Lexus
A hum under braking, a bearing in the transmission
The noise rises with road speed, not with petrol engine revs. We locate it on the road and only then do the work, on the transmission, not on the petrol engine.
Toyota Prius third generation
Misfires and knocking from a clogged EGR circuit
Carbon mixed with oil blocks the EGR cooler and pipes, and the engine misfires, especially when cold. Cleaning or replacing the EGR parts solves it; ignored, it can lead to head gasket failure.
What the work covers and what it doesn’t
The warranty covers the work on the confirmed cause, under the conditions on the handover sheet. It is not a warranty on the whole drivetrain.
A warranty on what we repaired
You get in writing what we replaced or repaired, what we measured and for how long we guarantee it.
Limits on major dismantling
If the repair needs extensive dismantling or hard-to-find parts, we tell you from the start the cost, the risks and the options.
If the problem is the inverter or the battery
Symptoms that look like engine trouble can come from the electronics or the high-voltage battery. We point you to the right check and don’t dismantle the transmission on a hunch.
Frequently asked questions about the hybrid motor and transmission
Do you also repair the petrol engine?+
Yes, especially the problems typical of hybrids, such as the clogged EGR circuit on the third-generation Prius. If a repair needs work we can’t do ourselves, we tell you straight.
What are MG1 and MG2?+
They are the two motor-generators in Toyota’s hybrid transmission. MG1 generates electricity, controls how the petrol engine’s power is split and starts the engine. MG2 drives the car, recovers energy under braking and handles reversing.
How long does the diagnosis take?+
It varies from case to case: it depends on how easily the problem can be reproduced and how much needs dismantling. We give you an estimate once we have located the problem.
Does every noise mean the transmission is faulty?+
No. It could be a wheel bearing, the differential, the mounts or the petrol engine. That is why we locate the noise on the road and from the data, not by replacing parts by ear.
Do you work on the Prius, Auris, Corolla, Camry and Lexus?+
Yes, on the common generations. Each has its own transmission specifics; when you book, we confirm what we can do on your car.
Do I need to bring the car on a tow truck?+
If it can no longer be driven safely or the noise is loud, yes. If it still drives normally, you can drive it in; we decide together when you book.
Find out where the noise or loss of power comes from
Book a diagnostic check. We tell you whether the problem is in the electric motors, the transmission, the inverter or elsewhere, before any needless dismantling.
Book a diagnostic check