Below post starts with car model 2001 GU Patrol (Y61) symptom that car kept going into limp home mode, then recommended to have one Foxwell AutoMaster Pro NT624 scanner to solved. How this story goes? Go on reading following parts. Hope it helps.

Car model: 2001 GU Patrol (Y61) with a 4.8 lt petrol

Symptoms:

My car kept going into limp home mode and i could not drive it (well).

Scan Tool to use:

Foxwell AutoMaster Pro Series tools: Foxwell AutoMaster Pro NT624

I use AutoMaster Pro NT624 to check ECU and read out fault code as below:

PO134 H02S1 (B1) – Heated O2 Sensor Bank 1 Sensor 1

P1122 ETC FUNCTION/CRC – Throttle Body Actuation -Electronic Traction Control

P1123 ETC Mot RLY/CRC – Electronic Traction Control – Motor Relay

After cleared the fault code, I got the left code:

P1122 ETC FUNCTION/CRC – Throttle Body Actuation -Electronic Traction Control

Then I have a quick check of the live data for the Throttle Body motor, when graphed against the Throttle Position Sensor, revealed that the throttle body motor was in-fact intermittently faulty. Causing a correlation error -Throttle position sensor not accurately reflecting the a accelerator position sensor.

Then I decided to do a quick check on the fault code:

PO134 H02S1 (B1) – Heated O2 Sensor Bank 1 Sensor 1

As this would take a drive cycle (potentially) to reset. We naviaged to the live data for the both O2 Sensors and graphed them together. With O2 Sensors, the general rule of thumb is to see them switch between rich and lean (0.1 -ish- and 0.9 -ish- Volts) around 8 times over 10 seconds at 2000 rpm. Watching each O2 sensor signal I counted the crosses (switching between 0.1 – 0.9) and found that wile the bank 2 (rear) sensor was crossing around 5 times (a lazy sensor) the bank 1 (front) was struggling to make 3 crosses. Both sensors where more often on the lean side. So although not technically a current fault, I was suggested to also replace my O2 sensors as they are both currently lazy -one more so than the other- and likely to need replacement in the future.
source:http://blog.foxwelltool.com/foxwell-professional-scanner/solved2001-gu-patrol-y61-going-into-limp-home-mode/