How to diagnose Landrover P0234 “reduced engine performance” error

Vehicle model:
Land Rover Freelander 2-(2.21 only) DPF diesel automatic
Vehicle identification number VIN: 001002x

The car feel like it has no power. The dashboard indicates: “reduced engine performance” message and(DTC)P0234-00 error code stored.

Diagnostic equipment:
JLR mangoose SDD/ JLR mangoose SDD Pro Win7 OBDⅡdiagnostic cable for Jaguar and Land Rover

JLR mangoose SDD

JLR mangoose SDD

JLR mangoose SDD Pro Win7

JLR mangoose SDD Pro Win7

Diagnosis analysis:

P0234 is a common untested DTC’s. It may caused by following reason:
1. Brake torque (brake on and throttle at wide open
2. Transmission oil temperature (TOT) exceeds calibrated threshold
3. Engine over temperature
4. Ignition misfire exceeds the calibrated threshold
5. Knock sensor (KS) failure

Here the error code is caused by first reason. Due to software defined blade position, the mechanical supercharger at ambient temperature is too low (below 20C) that can not provide the required boost power.


1. JLR Mangoose SDD diagnostic software must be loaded with 16 IDS DVD 118.5 or higher version

2. Well connect Midtronic storage battery with vehicle.

3. Connect Mangoose SDD/IDS cable to vehicle

4. When JLR SDD OEM diagnostic cable is well connected with vehicle, the system will automatically read the Vehicle identification number (VIN) and then confirm it. Start diagnostic procedures.

5. IDS/SDD than will detect vehicle information

6. The system will pop out message reading “Do you wish to read diagnostic trouble codes?
Select “√” mark and continue.

7. Select “Content Model” message, select “Vehicle Configuration” option

8. Select “Special Applications”

9. Select “Powertrain”

10. Select “P0234(turbochargeroverboost)calibration reflash”

11. Follow the system prompts

12. Exit the program when all procedures are complete

13. Disconnect JLR car diagnostic tool and storage battery.

Video: V139 JLR Mangoose Pro Install Video