The 48V DC/DC converter (label ETYAA, "DCDC CONVERTER 48V-12V") is fitted to Jaguar Land Rover mild-hybrid (MHEV) vehicles. It takes power from the 48V system and supplies the 12V network, including charging the 12V battery. When it fails, the car usually shows charging or electrical warnings and the 12V battery runs flat.
Common symptoms
- 12V battery not charging or repeatedly going flat
- Charging system, hybrid system or electrical fault warnings on the dashboard
- Stop/start not working, reduced functions or no-start
- Fault codes stored in the DC/DC converter or related modules
Fault codes
| Code | Meaning |
|---|---|
| P0A94 | DC/DC converter performance |
| U-codes | Lost communication with the converter (CAN network), check wiring and supply first |
Send us the full code list read from the vehicle, including codes from other modules. It helps us check the right area first.
P0A94 (DC/DC converter performance) often leads us to test the power section. P0D33 (DC/DC converter current high) can point to the control electronics or to output-stage components. For P0D22, U0064, U3008 and similar codes, read the full JLR description and sub-code from the vehicle. No fault code on its own is proof that a specific component has failed.
Which part number do you have?
The part number is on the white label as CPN, for example L8B2-14B227-AD or K8D2-14B227-AM. Please also note the SW V (software version) shown on the label. Revisions do not fail equally often and do not all need the same repair, so the service we offer depends on the exact part number, electronics revision and fault.
| Family | What to know |
|---|---|
| K8D2 / K8B2 | Early MHEV converters. Repair depends on the fault found on the bench. |
| L8B2 (incl. L8B2-14B227-AD) | The unit we are asked about most often. |
| N8B2-14B227-AA / AB | Assessed by part number and fault. |
| N8B2-14B227-AC and later | Different hardware design; testing and repair availability must be confirmed individually before sending the unit. JLR service information (SSM 76173 / 76174) covers inspecting this converter and its harness connector for damage. |
| NK62 | Individual verification before we accept the unit. |
Different part numbers are not automatically interchangeable. If yours is not listed, send us a photo of the label before posting the unit.
How the 48V and 12V systems work together
This diagram shows the functional layout only. We do not publish connector pin assignments for the 10-pin control connector: CAN-H, CAN-L, wake-up and control-supply pins have to be confirmed in JLR TOPIx wiring diagrams for the exact vehicle and part number.
Check these before condemning the converter
- 12V battery condition and charging voltage
- 48V battery and BECM fault memory
- Connectors and wiring at the converter (corrosion, damage, poor contact)
- Software level and available updates
- CAN communication with the other modules
Recalls and service actions
Check your vehicle on the GOV.UK vehicle recall checker and ask a Jaguar or Land Rover retailer about service actions and software updates. In the USA, NHTSA recall 26V248 (April 2026) describes DC/DC converter failures caused by an internal fault in a boost control chip on several MHEV models. A US recall does not automatically mean an identical action in the UK.
How we test and repair it
Every unit goes through the same T-Tronic Lab procedure and gets its own TTR job number:
- Intake: photos, housing condition, signs of water ingress, corrosion or previous repairs.
- Identification: part number, hardware/software version, symptoms and fault history.
- Documentation and data backup: where possible, the memory is read and saved before any work.
- Safe bench test: current-limited power-up, supply and communication checks.
- Diagnosis: we locate the fault area: power stage, supply, communication or control.
- Decision: repair, or return as unrepairable. Any extra cost is quoted first, nothing is done without your approval.
- Repair and final test, with the measurements recorded.
- Report: PASS, PARTIAL or FAIL, with what was tested and the limits of the test.
- Return shipping with tracking.
Use your order or TTR reference to request a progress update by email or WhatsApp. We send tracking when the unit is dispatched.
What we check on the bench
| Test | What it tells us |
|---|---|
| Current-limited power-up on the 12V and 48V side | Short circuits and abnormal current draw, before full power is applied |
| Quiescent (sleep) current | Whether the unit drains the 12V battery when the car is parked |
| CAN communication | The unit wakes up, communicates and reports its fault memory |
| Supply rails on the board | Internal power supplies for the control electronics are correct |
The measured values are recorded on your TTR job and the final report states which tests were passed and what was not tested.
Prices, reports and warranty
| Service | Price |
|---|---|
| Diagnostic assessment with written report | £80 – deducted from an approved repair |
| Standard repair of your converter | £630 – standard repair; extensive damage quoted |
| Advanced repair / rebuild (power stage, multiple faults) | Individual quotation |
| Reconditioned exchange | Price and availability on request; data transfer scope confirmed |
| Cloning / data transfer | £80 |
| We buy faulty converters | Individual offer |
Assessment and standard repair can be booked through the relevant service page after compatibility is checked. Exchange supply and non-standard work require a written quotation. No VAT added – we are not VAT registered. Return delivery is agreed with you before it is charged. Example: a £630 repair after an £80 assessment costs £550 more.
You receive two reports: an Initial Diagnostic Report after the assessment (measurements, fault codes, CAN result, tests performed and their limits, feasibility and quotation) and a Final Repair & Test Report after repair or exchange (work done, before/after results, functional tests and load tests if performed). A test that was not carried out is shown as not tested, and the overall result is shown as partially tested when a required check is missing.
Warranty & testing FAQ
How long is the warranty? Repaired and reconditioned converters come with a 12-month limited warranty covering the work performed and the components specified in your service documentation. See our warranty terms.
Do I need a new 12V battery? The 12V battery and charging system must be checked before fitting. Where our assessment requires it, a new, correctly specified 12V battery must be fitted – we tell you before you approve the work. Keep the invoice and fitting date.
What is not covered? The vehicle, the 48V battery and other modules. Later damage from water, incorrect connection, wiring faults, overvoltage, an unsuitable battery or third-party work is assessed separately. Your statutory rights are not affected.
Ask for a diagnostic assessment – £80Check compatibility on WhatsApp