Lexus Hybrid Auxiliary Transmission Oil Pump Repair
We specialise in repairing the auxiliary transmission oil pump fitted to hybrid Lexus models. A failed pump leaves the gearbox without proper oil pressure and can cause serious damage to the hybrid transmission. We repair or rebuild the pump – faster and cheaper than fitting a new part from a Lexus main dealer.
Photos from a Lexus Hybrid auxiliary pump repair
The photos show an auxiliary pump stripped right down: the gerotor rotor with its cover and o-ring seal, the brushless motor rotor, and the Hall sensor board hidden inside the pump body. It is these three assemblies that decide whether a pump can be rebuilt: a worn gerotor profile and a worn shaft seat cut the delivery rate, so the control unit stores the pump performance code (P2797), while a damaged Hall sensor board breaks the rotor position feedback — the pump motor loses commutation, stalls, and the motor stalled code (P0C2A) appears. We assess the condition of each of these parts once the pump is stripped, before quoting for the repair. The last photo is the Denso label from the pump body – every number we read off it is collected in the table in the "Auxiliary pump part numbers" section.
Workshop videos – the Lexus Hybrid auxiliary pump
Two short clips from our workshop. The first shows an auxiliary oil pump removed from a hybrid Lexus, seen from the mounting flange side, with the drive shaft protruding and the seat for the pumping mechanism; this is what the part that comes to us for a rebuild looks like. The second is a before-and-after comparison: the engine bay of a Lexus hybrid, followed by the rebuilt pump refitted to the transmission, filmed from underneath the car.
What is the problem?
Hybrid Lexus models with the L110 transmission – the GS450h and the LS600h – have an additional, electric auxiliary transmission oil pump. It keeps oil pressure up even when the petrol engine is switched off, that is in electric driving mode and at every standstill with the engine shut down. The RX450h also has an electric transmission oil pump. Over time the pump wears out – the bearings, the gerotor rotor and the seals lose their efficiency, which leads to a drop in oil pressure and to the gearbox working incorrectly.
A failed auxiliary pump leaves the gearbox without proper oil pressure and can cause serious damage to the hybrid transmission. Reacting to the first symptoms early saves you the cost of replacing the whole gearbox.
Symptoms of a failed auxiliary pump
- No EV driving mode – the car will not switch to electric drive even with a charged HV battery
- Gearbox limp mode – the gearbox drops into limp mode, with power and available ratios restricted
- "Check Hybrid System" message – a dashboard warning relating to the hybrid system
- Juddering when pulling away – vibration and jolts felt as the car sets off from a standstill
- No drive at all – the car does not move with a gear selected – no drive whatsoever
- Distinctive noises – scraping, rubbing, whining or droning coming from the gearbox area
- Unnatural pump noise – the pump still runs but sounds worrying – a sign of wear
Supported models with an auxiliary pump
Lexus Hybrid
- Lexus GS450h – 2006-2020, V6 3.5 Hybrid (L110 transmission)
- Lexus LS600h – 2007-2017, V8 5.0 Hybrid (L110 transmission)
- Lexus RX450h – 2009-2022, V6 3.5 Hybrid – electric transmission oil pump
Auxiliary pump part numbers
Plenty of people look for this part by the number on its label. The Denso label sits on the black body of the pump motor: the first line is the part number (e.g. 56010-HRA030), the second the internal Denso number (e.g. 064800-0023), and the third the 12 V supply voltage plus an extra factory marking. The table collects the markings of pumps that have actually passed through our workshop – we add to the list with every further repair.
| Label number | Denso number | Toyota / Lexus OE numbers | Application |
|---|---|---|---|
56010-HRA030Denso · 12V 06H27 0028 | 064800-0023 | 35300-30022 35300-30030 35300-30031 35300-30032 | Lexus GS450h (GWS191, 2GR-FSE) – auxiliary oil pump for the L110 hybrid transmission |
In the Toyota and Lexus catalogue the complete pump (PUMP ASSY, OIL W/MOTOR) has been through successive revisions – a newer number supersedes the older one, so for the GS450h the number currently ordered is 35300-30032. Not sure whether your pump is the same part? Take a photo of the label and send it to us – we will compare the numbers and tell you whether the pump can be rebuilt.
Fault codes linked to the auxiliary pump
Auxiliary oil pump faults
| Fault code | Description and cause |
|---|---|
P2797 | Auxiliary Transmission Fluid Pump Performance / Stuck Off – the auxiliary oil pump is not delivering what the control unit has asked for. The "Performance" variant points to mechanical wear inside the pump itself, the "Stuck Off" variant to a control circuit that never switches the pump on. |
P2798 | Auxiliary Transmission Fluid Pump Control Circuit Low – the voltage in the auxiliary pump control circuit is too low. This is an electrical code: it points to a break or a short in the wiring, a corroded contact or a failed output stage in the control unit, and not to oil pressure itself. |
P0C2A | Auxiliary Transmission Fluid Pump Motor Stalled – the auxiliary pump motor has stalled or is jammed. The typical cause is a seized pump mechanism, a damaged shaft bearing or a lost signal from the rotor position sensors. This is a generic SAE code for auxiliary pumps – on a Lexus you will normally read it as a manufacturer code. |
P0C2B | Auxiliary Transmission Fluid Pump Control Module Feedback Signal – a fault in the feedback signal from the pump control module. The module's self-test detects an incorrect supply or no confirmation that the pump is running. Also a generic SAE code for auxiliary pumps. |
Do not ignore the symptoms!
An auxiliary pump can still be running while making unnatural noises – scraping, rubbing, whining or droning. That means it is progressively wearing out and risks leaving the car immobilised without warning. Driving with a damaged pump can cause serious and expensive damage to the whole hybrid transmission.
What we offer
- A professional repair / rebuild of the auxiliary pump
- Pressure testing after the repair
- A warranty on the repair carried out
- A far cheaper alternative to a new part from a Lexus main dealer
Why choose us?
- Lexus Hybrid specialists – experience with auxiliary pumps from hybrid transmissions
- Pump rebuild – a professional repair instead of a costly replacement with a new part
- Testing after the repair – pressure testing and a check road test
- Warranty – a warranty on the repair carried out and on the parts used
- A cheaper alternative – far lower cost than a new pump from a Lexus main dealer
- Quick turnaround – the repair takes 1-3 working days
How the service works
- Phone consultation – we go through the symptoms, the fault codes and the vehicle's history
- Bringing the car in – a visit to our workshop with the car
- Diagnostics – reading the fault codes, testing the pump, measuring oil pressure in the gearbox
- Removing the pump – taking the auxiliary pump off for inspection and repair
- Rebuild / repair – replacing the worn components, rebuilding the pump mechanism
- Refitting and testing – refitting, a pressure test, clearing the fault codes
- Road test – a check road test confirming that the pump and the gearbox work correctly
Pricing
| Service | Description | Turnaround time |
|---|---|---|
| Pump diagnostics | Reading the codes, measuring oil pressure | Free with a booked repair |
| Auxiliary pump rebuild | Repair of the gearbox oil pump mechanism | 1-3 days |
| Replacement with a new pump | Fitting a new pump (if a rebuild is not possible) | Quoted individually |
| Fault code clearing + adaptation | Resetting the codes, adapting the gearbox control unit | Included in the repair price |
* Exact quote after diagnosis. The price depends on the condition of the pump and the scope of work required.
For workshops and garages
We work with Lexus/Toyota workshops and service centres. We offer auxiliary pump repairs as a service for other workshops. Get in touch for details of our B2B terms!
Get in touch
Is your Lexus Hybrid showing a 'Check Hybrid System' message? Does the gearbox drop into limp mode? Can you hear strange noises from around the gearbox? Get in touch to talk the problem through and get a quote for the auxiliary pump repair.
We also repair other gearboxes
Frequently asked questions
Which Lexus models does this auxiliary pump fit?
The electric auxiliary transmission oil pump is fitted to hybrid Lexus models with the L110 transmission, that is the GS450h and the LS600h – it keeps oil pressure up even when the petrol engine is switched off. The RX450h also has an electric transmission oil pump, as do the related Toyota models. It does not apply to the IS300h, RC300h or NX300h: their hybrid transmissions have only a mechanical pump driven by the petrol engine.
What are the symptoms of a failed auxiliary pump in a Lexus?
The most common symptoms of a failed auxiliary oil pump in a hybrid Lexus are: no EV driving mode, the gearbox dropping into limp mode, a 'Check Hybrid System' message, juddering when pulling away or no drive at all, and distinctive scraping, rubbing, whining or droning noises from around the gearbox. The control unit memory then usually holds code P2797 (auxiliary pump performance) or P2798 (pump control circuit); when the pump motor has seized, codes from the P0C2x group appear as well.
How much does an auxiliary pump repair cost on a Lexus Hybrid?
The cost of repairing an auxiliary transmission oil pump depends on how worn the pump is and on the work it needs. Rebuilding the pump is far cheaper than buying a new part from a Lexus main dealer. Get in touch for an individual quote – after an initial phone consultation we will give you a ballpark figure.
Can the pump still work but make strange noises?
Yes – an auxiliary oil pump can still be running while making unnatural noises: scraping, rubbing, whining or droning. That means it is progressively wearing out and risks leaving the car immobilised without warning. We recommend having it diagnosed and repaired as soon as possible.
What happens if I ignore a failed pump?
A failed auxiliary pump leaves the gearbox without proper oil pressure. Driving with a damaged pump can cause serious and expensive damage to the whole hybrid transmission, up to and including having to replace the gearbox.
What is the part number of the auxiliary pump in a Lexus GS450h?
The body of the electric auxiliary oil pump from a hybrid Lexus GS450h carries a Denso label with the number 56010-HRA030 on the first line and the internal Denso number 064800-0023 on the second; the third line is the 12 V supply voltage plus an extra factory marking (06H27 0028 on our example). In the Toyota/Lexus catalogue the same pump as a complete assembly (PUMP ASSY, OIL W/MOTOR) appears under the numbers 35300-30022, 35300-30030, 35300-30031 and 35300-30032, with each later version superseding the previous one – the number currently ordered is 35300-30032. If the number on your pump is different, send us a photo of the label – we will compare the markings before accepting the part for a rebuild.
How long does a Lexus auxiliary pump repair take?
A standard repair or rebuild of an auxiliary oil pump usually takes 1-3 working days, depending on the condition of the pump and on parts availability. Once the repair is done we carry out pressure tests and a check road test.