2015 Lexus RX350

Jeff Manager California Posted   Latest  
Resolved
Driveability
2015 Lexus RX350 3.5L (2GRFE) 6-spd (U660E) — 2T2ZK1BA0FC208158
P0500 — Vehicle Speed Sensor "A" Circuit
Hiccup On Accel

Looking for a waveform for the vehicle speed input to the Engine Computer. This system uses ABS to get the vehicle speed. ABS sends a square wave to the Instrument Cluster. Cluster then send the square signal to the rest of the computers that need the signal. I need a known good waveform to compare my signal against. My information system states the signal should be a 12 or 5 volt square wave. 

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Interesting
Benjamin Diagnostician
Connecticut
Benjamin
   

5̵V̵ ̵s̵q̵u̵a̵r̵e̵ ̵w̵a̵v̵e̵,̵ ̵a̵c̵c̵o̵r̵d̵i̵n̵g̵ ̵t̵o̵ ̵t̵h̵e̵ ̵m̵a̵n̵u̵a̵l̵,̵ ̵ 12 V (thanks for correcting me) in 4-pulse bursts. Hope this helps, I don't have a wave to share atm, but maybe something will show up?

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Philip Educator
California
Philip
 

My problem car was a Toyota Camry. My service info said 5 volts but it wasn't 5 volts. I had a P0500 in the PCM but the speedometer worked and no problem in the ABS. I tapped the signal wire to ground between the IC and the PCM and I could generate an RPM signal. But I believe the problem was a bad ground in an aftermarket radio circuit that was causing the problem. After I taped with the test…

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Rich Service Manager
New Hampshire
Rich
 

Just checked a 2012 RX350 2 weeks ago that had a vehicle speed signal code, The wave form was a 12 volt signal. Speed is calculated in ABS, then sent to cluster, from there to a junction left side J/C F93 of dash where they are sent from that junction to the other modules. So you should be able to concentrate on the the wire from PCM back to that junction. HTH

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Saifullah Diagnostician
Ontario
Saifullah
 

If you are worried about resistance/open, just run a quick overlay. Will rule out open or high resistance.

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Jeff Manager
California
Jeff Resolution
 

Thanks for all the help. The waveform from Phil definitely proves that mine is being manipulated by another computer or that the harness has damage somewhere. The customer didn't want to pay anymore labor to find out about their problem, but I did take a screen shot of my signal so people could see a known bad one. My best guess is that the engine computer is the one at fault because wiring…

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Benjamin Diagnostician
Connecticut
Benjamin
 

With the low voltage, I'd suspect high resistance, likely due to bad wire harness repairs. If the repairs were an insurance job, maybe they could open a supplement?

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Jeff Manager
California
Jeff
 

Yeah Benjamin, I wish the customer was willing to let me check it out some more so I could prove what the actual cause was.

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Agree