NickySB

Installed a fly lead from the connector back to the ecu pin, checked again but code still remaining. That would rule out the harness.

Finally managed to get the terminal pins out today. I was expecting to find corrosion or a snapped pin within but sadly nothing found - all connections were good and clean.

I realise I'm well overdue an update on this thread. Not been able to borrow a compressor as I don't know any other GS owners. I've gone through the Lexus testing relating to this specific code (P3108-535). The guidance says DTC P3108-535 may be stored due to an open circuit in the SMRB circuit or SMRG circuit Voltage& resistance checks, but I checked the various voltages/resistances on 2 separate occasions and observed the following (under various power on or off scenarios as dictated by guidance): CLK port on motor connector to ground is good for voltage CLK port on motor connector to CLK on ECU connector is good for resistance CLK on ECU connector to ground is good for resistance ITE on ECU connector to ground is good for voltage ITE on ECU connector to DIM on motor connector is good for resistance TE on ECU connector to ground is good for resistance ETI on ECU connector to ground is good for voltage ETI on ECU connector to DOUT on motor connector is good for resistance ETI on ECU connector to ground is good for resistance DOUT on motor connector to ground is NOT GOOD for resistance DOUT on motor connector to ground has good voltage DIM on motor connector to ground has good voltage The obvious suspect in that is the DOUT (3rd port from left) on motor connector, which would imply its a problem somewhere in the harness) however the guidance continues to point at hybrid ECU or hybrid ecu wiring harness ( i think that is P/N 82121-30D20). When the DOUT is checked, the ECU connector is in place and the power is off. As the ECU is connected at that point I can't rule it out. When ETI is measured from the hybrid ECU connector to DOUT for resistance, it is within spec.

went back to oem exhaust manifolds and fault resolved

OEM exhaust manifolds are IRO £654 per side. As I understand it, the sensors in the manifold are air fuel ratio sensors. I am not particularly suspicious of those because the car is running well, still achieving 40mpg and they’re situated before the cat on the manifold, so I guess yes, it can only be the manifold cats

Hi Everyone The flanges on my original exhaust were rusting away so I opted to replace the entire system ( exhaust manifold, centre pipe & back box ) - due to cost I opted for a pattern system. As soon as the work was complete the GS (450h) started generating the P0420/P0430 codes, I suspect due to substandard cats in the centre section ( not OEM). I’ve tried various roots to resolve (new sensors / spacers/ confirming no leaks etc ) and it still won’t stop generating. A check on TechStream confirms the sensors are working fine but they’re outside the tight margin in the current set up. I’ve not found anyone who can manage to open the threshold on the ECU settings. Emulators for the 450h don’t exist so I’m running out of options other than replacing the centre section with OEM ( current list price £1340.06) - has anyone else come across the same and found a work around ? Does wiring a resistor into the O2 sensor resolve ? Thanks

Hi, yes you offer a good perspective and I think you’re probably right. I believe it is part of it ( but I’ll happily be corrected by those more in the know). I will try to conduct a test with another harness/compressor. Thanks

I completed an engine tear down on mine when it developed some odd behaviour ( shaking & refusing to start on occasion) , after lots of investigation rebuilt the top end, no change, tore it down again to eventually identify a bent Conrod in cylinder 4. I would argue an engine change was easier than a rebuild but that’s just my opinion if that’s what you decide to do, unless that’s now the donor car you mention in other posts

I should have clarified though that the kw gauge still works

I’ve gone through the fault finding from start to finish , regardless of the flow chart, and other than having excess voltage as mentioned above between pin 5&6 on the compressor connector, the only other finding was poor ( over loaded) resistance reading between DOUT ( pin 3) on the connector & body ground. The flow chart points at the connector/harness for the excess voltage and the ECU for the resistance issue. Initial thoughts are I’m still struggling to see how the voltage gets dropped from the circuitry so I’m inclined to focus on the ECU

Gone through the wiring diagram and looking at the circuit start to finish there doesn’t appear to be anything that drops the voltage so I’m not entirely clear why it should be testing below 1v, more investigation to follow

A few more hours fault finding today using the guidance in the manual via Lex Tech. I checked the connector to the compressor again just to make sure I got the same. I can’t have checked properly before as I got different readings. The resistance was within spec ( under 1 ohm) but voltage was not, it should be under 1 v in the specified condition (power on, pin 5 to pin 6) but it reads 11.74v same as the battery, so it looks like the cause is either the connector or the wiring harness.

Thanks that’s useful background. Yes the dash display for the battery charging is also absent of arrows but does show the wheel & battery

Hi everyone Since my engine change in late 2021/early 2022 I’ve has an odd issue of the energy flow arrows for the hybrid not showing. Everything else on it replicates - charging battery, spinning wheels but the arrows have gone awol. it’s been a bit of a ride since the engine was replaced with the 3rd or 4th hybrid battery rebuild then the local garage blowing up the inverter some 6 months or so later during welding for the MOT, however not a Toyota/Lexus hybrid specialist nor the dealership themselves are familiar with this scenario or have been able to find the cause. I wanted to document my attempts to resolve so far in case it helps someone else out when I (hopefully) get a fix. 1) no apparent hybrid battery wiring harness damage- there doesn’t appear to be any broken/pinched/visibly degraded wires and all fuses are good. 2) a lot of Prius owners loose their screen when the 12v battery thermistor fails. I’ve tried changing mine, no change. 3) using TechStream I had codes B1498 - Communication Malfunction A/C inverter local & P3108 Lost Communication with AC system control module. After reading up I found during engine changes the AC compressor connector can get coolant in it and corrode. Checked the socket and it was corroded. I had also recently had the system regassed at Lexus (after the engine change I’d left it empty ) and it held pressure but wouldn’t blow cold. I tried to clean the socket on the compressor up but when the plug went back on it went back on out of line and bent the pins, so I fitted a replacement compressor, B1498 is now historical but p3108 remains. I’ve not had it regassed to try the AC function yet. 4) there’s nothing on TechStream when I go into the hybrid summary which shows any relevant degradation. 5) I’ve checked the voltage and resistance on pin receptors 5 & 6 on the black plug which at attaches to the compressor and it’s within spec of the Lexus manual 6) CAN BUS check on TechStream shows all units are white which means Currentlu Communicating on the CAN BUS. the saga continues

With the help of a friendly Lexus dealer I’ve got to the bottom of it. My car needs to the PMV-107J sensors which is 433 MHz. I’ve tried the PMV-107K and they don’t work, and neither have any other 315-433 MHz alternatives , so I have to replace with the original P/N 42607-30042 or at least a PMV-107J and they seem to not be so common