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My brother owns a 2005 RX330 3.3v6 and it died on him while driving. We towed it home and found the fuel pump not working. I replaced the fuel pump and now it's working. I have a crank but no start situation. I put a cheap code reader on it and i get a PO340 code. So I replaced the camshaft position sensor and still no start. After that I have two codes now. PO340 sensor A circuit bank 1 and PO345 sensor A circuit bank 2. I tested the circuit with a multi meter and have an open circuit from battery ground to connector ground. I'm thinking loose or broken wire. So my question is does this circuit run to the fuse box and then to the ECM? All fuses under the hood are good. In the back of my head I've been thinking maybe the motor jumped time until I tested the circuit. I also ohmed out the new sensor and it has proper resistance. Battery and starter are fairly new as well. I am no expert and need some advise from someone please.
Not likely the timing belt jumped and the fuel pump goes out at the same time.
Critical the battery voltage doesn't fall too low while cranking.
Critical that the engine and frame grounds are perfect.
"Positive Terminal to Engine" should match the battery's voltage(some of the ECM's peripherals use the engine's ground).
"Positive Terminal to Frame" should also match the battery's voltage(ECM motherboard uses a frame ground).
Plz see fuel pump circuit.
Fuel pump failure noted by OP. Fuel pump has frame ground.
Fuel pump is powered by C-open relay
Follow C-Open relay coil energizing wire(orange) follows back to ECM ECM has frame ground
Plz see VVT Sensor LH & VVT Sensor RH(cam sensors) and Crankshaft Position Sensor Circuit.
Cam sensor codes noted by OP
Crankshaft Position sensor output is compared to VVT(cam sensor) outputs by Ecm to determine if the cams are hitting the exact cam angles needed.
All 3 sensors share a special common ground provided as a dedicated Ecm outout located on Ecm at Connector C, Pin24, NE- ECM has frame ground
Not saying grounding issues & battery voltage issues are 100% the problem but it's very suspicious how the fuel pump and wild ECM codes can be related when "going in deep".
You may have a slipped T-Belt and fuel pump failure, who knows- a 1 in a million- but hope you see how complicated a diagnostic can get by spit balling and guessing. From the info provided by OP I would check voltages, alternator, grounds, and do more testing & post more info.
Wishing you success, plz let us know how it goes and hopefully more people have ideas too.
Last edited by Margate330; Oct 1, 2021 at 02:51 AM.
Not likely the timing belt jumped and the fuel pump goes out at the same time.
Critical the battery voltage doesn't fall too low while cranking.
Critical that the engine and frame grounds are perfect.
"Positive Terminal to Engine" should match the battery's voltage(some of the ECM's peripherals use the engine's ground).
"Positive Terminal to Frame" should also match the battery's voltage(ECM motherboard uses a frame ground).
Margate330 - Thank you so much for the reply. I will check battery voltage while cranking and see what I read as well as the frame grounds. I'm not sure where to check positive terminal to engine. This brings me to another question. Positive terminal to frame? If the frame is used as a ground, how will there be positive energy there? Sorry if this is a stupid question but I'm confused. Thanks again for your help and I will make sure to post results so it may help someone else.
Margate330 - This information is great. If I could afford to have a professional look at it I definitely would. Going to dig a little deeper into this and will post results asap. Thanks again!
///////// Next 3 pics are keys on but not started, no a/c, no accessories- compare voltages again ///////////////////////////
Checking battery voltage, keys on, engine not running
Positive terminal to engine, keys on, engine not running
Positive terminal to frame, keys on, engine not running
There is lots more stuff that can be checked after you are confident you have proper voltages and ground.
Plz let us know how it goes and if you get it fixed.
Last edited by Margate330; Oct 1, 2021 at 03:24 PM.
Thanks again margate330. I've tested the battery some of the ways you've shown but not all so I will do this today, I was overthinking again LOL. I'm slow to get out there and do this because of a bad back but will post results asap!
Thanks again margate330. I've tested the battery some of the ways you've shown but not all so I will do this today, I was overthinking again LOL. I'm slow to get out there and do this because of a bad back but will post results asap!
UPDATE!
OK, It seems that the timing belt either jumped or broke. I ended up doing a dry compression test on cylinder #1 and the reading was 65psi. NOT GOOD! So naturally my next question is. Is this an interference engine? I guess I need the engine code or VIN# to be sure but if anyone knows off the top of their head it would be great to know.
A dead fuel pump that you replaced doesn't go with a slipped Timing Belt with cam codes- something does not add up.
-> Was hoping for you they were related in a "non- mechanical way".
Now with reported 65 psi compression on cylinder #1 this changes everything and the fuel pump is out of the equation.
That's Ok though, only takes 5 mins to check voltages and grounds so at least that's done.
Moving on...
Some people say this is inteference engine and some say it's only inteference if the cam timing is advanced by the ecm while running during a timing belt break- so I don't know as I never been able to confirm 100% on anything(maybe someone else knows). I've seen it cited in many places like everyone else about it being inteference(including the service manual) but myself and others have turned the cams by accident while doing a timing belt installation with no piston crash. The service manual warns about inteference damage during timing belt replacement too.
Not sure your DIY capabilites but if it was my car I would pull the timing cover and check my timing marks see what's going on and get some answers since with 65 compression you have a reason to go in there. Your timing belt probably had white lines on it for lining it up during installation but they seem to disappear over time.
This is ok because timing marks are notched on the cam gears and they line up on the metal timing belt rear cover. The crank shaft has it's own marks to check(see pics below). Also, lots of good videos on youtube for timing belt for reference.
The way I understand it the crank has to be turned 60 degrees CCW from this point to keep the pistons out of the way so the cams can be turned safely.
Last edited by Margate330; Oct 5, 2021 at 06:45 PM.
A dead fuel pump that you replaced doesn't go with a slipped Timing Belt with cam codes- something does not add up.
-> Was hoping for you they were related in a "non- mechanical way".
Now with reported 65 psi compression on cylinder #1 this changes everything and the fuel pump is out of the equation.
That's Ok though, only takes 5 mins to check voltages and grounds so at least that's done.
Moving on...
Some people say this is inteference engine and some say it's only inteference if the cam timing is advanced by the ecm while running during a timing belt break- so I don't know as I never been able to confirm 100% on anything(maybe someone else knows). I've seen it cited in many places like everyone else about it being inteference(including the service manual) but myself and others have turned the cams by accident while doing a timing belt installation with no piston crash. The service manual warns about inteference damage during timing belt replacement too.
Not sure your DIY capabilites but if it was my car I would pull the timing cover and check my timing marks see what's going on and get some answers since with 65 compression you have a reason to go in there. Your timing belt probably had white lines on it for lining it up during installation but they seem to disappear over time.
This is ok because timing marks are notched on the cam gears and they line up on the metal timing belt rear cover. The crank shaft has it's own marks to check(see pics below). Also, lots of good videos on youtube for timing belt for reference.
The way I understand it the crank has to be turned 60 degrees CCW from this point to keep the pistons out of the way so the cams can be turned safely.
That's exactly what I'm going to do. I'll pull the cover and inspect. I got the same mixed answers as to if it's an interference motor or not, so it's worth it to me to check. I hope there's no damage to the pistons or valves from them crashing into each other and hopefully if it is an interference motor, the ECM shut it down in a way that didn't cause serious damage or I possibly got lucky. Who knows. I can do a belt replacement with a little help from a friend who has a garage nearby. Gonna have to find TDC and all that but not too worried. I'll update ASAP. Thanks again for your help, you've been great!
That's exactly what I'm going to do. I'll pull the cover and inspect. I got the same mixed answers as to if it's an interference motor or not, so it's worth it to me to check. I hope there's no damage to the pistons or valves from them crashing into each other and hopefully if it is an interference motor, the ECM shut it down in a way that didn't cause serious damage or I possibly got lucky. Who knows. I can do a belt replacement with a little help from a friend who has a garage nearby. Gonna have to find TDC and all that but not too worried. I'll update ASAP. Thanks again for your help, you've been great!
This mystery keep puzzling me.
-> Could it be possible that the ECM made a special "fault exception" upon determining a DOUBLE CAM ERROR when compared to the Crankshaft Position Sensor and killed power to the fuel pump as a protective measure?
This could explain leading the owner to replace a fuel pump, however if this exception is in the manual I never found it and never heard about anyone reporting it, maybe someone knows.
Yeah, the guessing is endless and trying to know what the ECM is thinking without some firmware source code is only speculation. lol
Hi Sctysct,
Just a courtesy post to see what they figured out on your car.
Forgot to mention, at idle our VVT's are fully retarded and do not advance unless rpm's are raised with throttle.
Edit- Just remembered you had a 65 psi compression, if your belt slipped would like to know if the engine is still ok.
Last edited by Margate330; Oct 13, 2021 at 08:32 AM.
Please Help!
