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So the day before I headed to Florida for a vacation I went to the local car wash and got an undercarriage wash and truck ran rough and stalled a couple of times. I went in for a haircut came out thinking maybe it dried out and wouldn’t start. I had the truck towed to by driveway and left for vacation. Before I left I plugged in the OBD2 and it threw out P0038(Ho2s heater control circuit high Bank 1 sensor 2) and P0335(crankshaft position sensor A circuit)both seem to indicate open circuits which occurred after high pressure water to the undercarriage. My thoughts that it most likely is a wet harness carrying power to the 2 sensors in question and needs to dry and maybe seal it with silicon.I’m hoping I get back and it starts without issues. I’ve sent a PM already to Acrad and that usually is my starting point lol. If not I’ll buy a crankshaft sensor and downstream O2 sensor from RockAuto. Have you ever heard of this issue? Thanks
"I vaguely remember someone having an issue but it could have been on GXOR. Wonder if water stream hit a harness connector serving both of these circuit? Both those sensors are in same general area... on rear driver side of engine"
"I vaguely remember someone having an issue but it could have been on GXOR. Wonder if water stream hit a harness connector serving both of these circuit? Both those sensors are in same general area... on rear driver side of engine"
I didn’t start today after vacation, when I get a chance I will check harnesses and plugs and check codes again. I will report back on my findings, Thanks everyone
Sliding under the truck on a 10 degree day wasn’t fun especially when it’s hard to determine if this is the crankshaft position sensor or not. It looks like it but can anyone confirm? Acrad attached a picture that shows a cover over the crankshaft sensor and this doesn’t have it. Thinking it is closer to the front of the truck
So a small update on my truck, had it towed to a local service station mechanic and when hooking up his OBD2 scanner it can’t communicate with the ECU. The scanner gets power and lists other functions but Can’t communicate with ECU or retrieve the last 2 CEL’s(P0038 and P0335). The mechanic suggested I tow it to Lexus as he doesn’t have the time to probe around and test wires and harnesses. So I towed it to my good friend that is a master mechanic(Not Lexus) he received the truck and started preliminary investigation. So he is trying to rule out ECU and having a hard time getting at the ECU which is to the right of the blower motor behind the glove compartment. He also ran out of light. He checked under the truck and wanted to test the plugs on the crankshaft and B1S2 O2 sensors but like myself found it extremely hard to reach them from on your back. My last resort is Lexus because I’ve had bad estimates that weren’t needed. If ECU is found to be faulty I’ll do a refurbished exchange, there are a few companies all of which are under $300, a lot better than $1000. I’ll post when I have more info.
This is really unfortunate. Given the rugged nature of these things, it seems improbable that they would not have critical components out of waters’ reach. My 13’s ABS light came on a couple of time after I went through a touch-less car wash with the undercarriage rinse. When I looked at it, the rubber protector flaps on the passenger’s side were not as intact as they could be. Replaced the bad one and it has not happened again and I go through that wash at least once a week.
When you get it fixed, post pics of where the component that got wet is. I would like to make sure that the part on mine is out of harms’ way.
This is really unfortunate. Given the rugged nature of these things, it seems improbable that they would not have critical components out of waters’ reach. My 13’s ABS light came on a couple of time after I went through a touch-less car wash with the undercarriage rinse. When I looked at it, the rubber protector flaps on the passenger’s side were not as intact as they could be. Replaced the bad one and it has not happened again and I go through that wash at least once a week.
When you get it fixed, post pics of where the component that got wet is. I would like to make sure that the part on mine is out of harms’ way.
yeah, I believe both of my front wheel wells need more coverage as I can see wires and harnesses from outside at the wheels. My problem has been exacerbated now because the OBD2 reads No Comms and my mechanic did some testing of wires and it seems the ECU is bad. He has pulled it out and I’m sending it out to a repair place called Neat Computers that has 100% rating on Ebay where it’s a $140 and repaired and sent back, and if it’s unrepairable or it tests ok you get your $$ back. The only drawback is it’s going to be about a week turnaround. I’ll advise when it comes back. I just thought fuses would have protected the ECU from a short circuit. I still would need to find the area that’s prone to get wet again. Thanks for your reply.
You (the mechanic) really should track down the root cause, otherwise it might just happen again. If water intruded upon the passenger footwell area and possibly damaged the ECU, the hood cowl seals and/or A/C drain should be inspected.
Interesting issue. Was there any evidence of water intrusion where the ECU was located? Seems unlikely to damage an ECU unless you had submerged it in water for a period of time. I suppose it is possible that the water underneath caused a short, but man, that seems like a 1:1,000,000 type situation.
Either way, it sucks. Hope you get it figured out.
Interesting issue. Was there any evidence of water intrusion where the ECU was located? Seems unlikely to damage an ECU unless you had submerged it in water for a period of time. I suppose it is possible that the water underneath caused a short, but man, that seems like a 1:1,000,000 type situation.
Either way, it sucks. Hope you get it figured out.
I sent out the ECU today FedEx and it should be tested and repaired, found to be not repairable or it tests ok and returned. Yeah I’m not loving just replacing the ECU without the root cause. It still seems like a wiring issue to me. I asked my mechanic to at least replace the crankshaft and O2 sensors the OBD originally showed faulty, that way if it’s a frayed wire it will be seen. Also asked to check the EFI relays(guess there is 2). So the only good thing I heard is the tow truck driver said he has seen this many times after an undercarriage wash because unlike a puddle it had high pressure jets of water shooting everywhere. If all else fails there is an electric specialty that deals primarily with Lexus’ 10 miles away, that’s where it would go. Def not Lexus.
No evidence of water intrusive in the passengers footwell where the ECU lays. Again makes me thing wiring issue because like Acrad said he thinks the ECU is protected by fuses and relays. Very aggravating to say the least and it’s like 6 degrees with snow storm on the way and my truck sits in my buddies driveway, not a good place to perform diagnostics
Interesting issue. Was there any evidence of water intrusion where the ECU was located? Seems unlikely to damage an ECU unless you had submerged it in water for a period of time. I suppose it is possible that the water underneath caused a short, but man, that seems like a 1:1,000,000 type situation.
Either way, it sucks. Hope you get it figured out.
Jacket I believe we both had a similar electrical issue with the ABS rear harness being shorted. That’s why I avoid Lexus dealerships from the beginning. Local Lexus dealer gave me an estimate for $2500 for complete ABS module which ended up being
A $100 ABS harness and still good to this day. I’m realizing my issues seem to originate with undercarriage water and wiring harnesses. Probably from all the corrosive salt used in the winters. I’m hoping this one is similar.
No evidence of water intrusive in the passengers footwell where the ECU lays. Again makes me thing wiring issue because like Acrad said he thinks the ECU is protected by fuses and relays. Very aggravating to say the least and it’s like 6 degrees with snow storm on the way and my truck sits in my buddies driveway, not a good place to perform diagnostics
10-4. Keep us posted. I get the pains of having to do any work in the winter. I am an ex-owner of an LS400, which left me stranded in the middle of winter once. Had no choice but to work on it in the freezing cold.. not fun at all. It ended up being the good 'ol ECU capacitor issue. Similarly, the car wouldn't start and also wouldn't detect a CPS CEL code until the capacitors were fixed. Due to the CPS fault, injector firing order was out of whack in parallel to the ECU being faulty. Just bad luck that it all happened at once. I have some videos on YouTube for educational purposes: youtu.be/yxwh1JafhGU
10-4. Keep us posted. I get the pains of having to do any work in the winter. I am an ex-owner of an LS400, which left me stranded in the middle of winter once. Had no choice but to work on it in the freezing cold.. not fun at all. It ended up being the good 'ol ECU capacitor issue. Similarly, the car wouldn't start and also wouldn't detect a CPS CEL code until the capacitors were fixed. Due to the CPS fault, injector firing order was out of whack in parallel to the ECU being faulty. Just bad luck that it all happened at once. I have some videos on YouTube for educational purposes: youtu.be/yxwh1JafhGU
Thank you, when you say ECU capacitor issues are they what goes bad inside the ECU or is that an external part I should consider? Thanks again.
Thank you, when you say ECU capacitor issues are they what goes bad inside the ECU or is that an external part I should consider? Thanks again.
Capacitors internal to the ECU. It was very straightforward to replace them, but this is an issue of the 90s. I could be wrong, but I believe it's a thing of the past and no longer happens on modern vehicles.
01-19-22, 10:57 AM
Truck won’t start after undercarriage car wash
