Hi, my Lexus gs300 will not crank and start after being fine when parked up the night before. The radiator fan will kick in when ignition is on but engine will not start. Check VSC has come up. When diagnostic laptop attached it is unable to connect to the ecu for fault code. All very strange as all fine when left last night. Checked fuses, security light flashing and battery ok. Have you any ideas please. Thank you lee

Asked by GuruDQQ6Y Sep 06, 2017 at 04:58 PM about the 2005 Lexus GS 300 RWD

Question type: Maintenance & Repair

Hi, my Lexus gs300 will not crank and start after being fine when parked up the night before. The radiator fan will kick in when ignition is on but engine will not start. Check VSC has come up. When diagnostic laptop attached it is unable to connect to the ecu for fault code. All very strange as all fine when left last night. Checked fuses, security light flashing and battery ok. Have you any ideas please. Thank you lee

3 Answers

170

Have a Tech check the CAS (rear of engine ) as they short the reff voltage from 5v to 4v and this pulls the reff v at the engine ECU. The processor wont work below 4.2volts. No coms no start. Cheers!

8 people found this helpful.
170

If you want to check it yourself, prove no coms with ECU. Disconnect Crank Angle Sensor (plug on rear of port head) then see if you can communicate. Couple of hours work to fit.

9 people found this helpful.
70

My VCS light also came on on my 06 GS300. My specific issue was the emissions. Turns out it was the gas cap that needed to be replaced and when I clear the codes out it never came back and the problem was solved. Why a faulty gas cap shut off the VCS light I have no idea.

2 people found this helpful.

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