Lane Keep Assist / PCS System Faulty.

[Jimmybay]

Hi all. I have recently imported a 2008 GGH20 and I'm delighted with it except for one nagging problem. It's a high spec 3.5 and includes radar cruise and lane keep assist. It seems that something isn't working properly and I get a warning on the dash (in the fuel gauge) flashing "PCS". This refers to the pre-collision system which I understand uses the various sensors on the vehicle to determine if a crash is imminent and pre-tensions seatbelts and possibly applies brakes amongst other things?

I've plugged in diagnostics and it shows error code B2051 "Malfunction of Lane Keeping Assist Sensor". I spoke with the exporter who was very helpful and suggested the fault was likely with the distance control computer located near the throttle pedal. They sourced me one and I installed it and calibrated it according to the service manual but it made no difference. They now suggest it could be the seatbelt computer. I was reluctant to just keep swapping ECU's in the hope it might fix the fault, so contacted a local Japanese vehicle importer who couldn't help. My local Toyota Dealer suggested they could help and booked me in for a diagnostic (they said their equipment could now read Japanese Import Toyota). Transpires they can't. In fairness they didn't charge me, but I'm now at a loss of where to look next. 

Does anyone have any knowledge of this specific system or fault, or know an independent with the ability to properly diagnose? The radar cruise works fine, so I'm assuming it's not the sensor behind the grill badge and if I approach stationery vehicles a little too quickly I get an audible warning, so I guess some parts of the system are working just fine. 

Apologies for such a long post. I'd be extremely grateful of any constructive advice. I'm located in Plymouth, but would travel if necessary. 

[Rojie]

On 12/23/2024 at 7:15 PM, Jimmybay said:

Hi all. I have recently imported a 2008 GGH20 and I'm delighted with it except for one nagging problem. It's a high spec 3.5 and includes radar cruise and lane keep assist. It seems that something isn't working properly and I get a warning on the dash (in the fuel gauge) flashing "PCS". This refers to the pre-collision system which I understand uses the various sensors on the vehicle to determine if a crash is imminent and pre-tensions seatbelts and possibly applies brakes amongst other things?

I've plugged in diagnostics and it shows error code B2051 "Malfunction of Lane Keeping Assist Sensor". I spoke with the exporter who was very helpful and suggested the fault was likely with the distance control computer located near the throttle pedal. They sourced me one and I installed it and calibrated it according to the service manual but it made no difference. They now suggest it could be the seatbelt computer. I was reluctant to just keep swapping ECU's in the hope it might fix the fault, so contacted a local Japanese vehicle importer who couldn't help. My local Toyota Dealer suggested they could help and booked me in for a diagnostic (they said their equipment could now read Japanese Import Toyota). Transpires they can't. In fairness they didn't charge me, but I'm now at a loss of where to look next. 

Does anyone have any knowledge of this specific system or fault, or know an independent with the ability to properly diagnose? The radar cruise works fine, so I'm assuming it's not the sensor behind the grill badge and if I approach stationery vehicles a little too quickly I get an audible warning, so I guess some parts of the system are working just fine. 

Apologies for such a long post. I'd be extremely grateful of any constructive advice. I'm located in Plymouth, but would travel if necessary. 

Hello Jonathan,

 

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