Jeza

DTC P0500 is a vehicle speed fault, not a gearbox speed sensor issue. Gearbox speed sensor faults are DTC P1820 and P1825. The speed signal comes from the wheel speed sensors to the skid control computer then to the combination meter, from there is a wire to the engine ECU, head unit, power amplifier and cruise control. Possibly in that line also is a chip to convert kph to mph. As the issue occured after installing your new head unit I would look at the speed signal wire to that. Grey connector, pin 3, violet colour

What about the cruise control you fitted, has that done something to the speed signal?

Hi There is no alternator on the hybrid, the aux battery is charged from the inverter / converter, 13.6v seems reasonable if the aux battery is fully charged. You have replaced the aux battery so the terminals should be good, check the earth straps, battery to body and body to engine. Anything wrong with the hybrid system would throw up codes. Could be the engine ECU, clutching at straws now without codes.

P3101-548 Abnormal signal received from engine control computer (CVT system abnormality) The hybrid vehicle computer performs fail-safe control based on an abnormality signal from the engine control computer (when the engine control computer detects an abnormality that may affect THS control). This points to the speed sensor on the gearbox as the signal goes to the engine ECU, then the hybrid ECU goes into limp mode. P1825 is the speed sensor circuit NOUT (speed out), wiring or the sensor, there are no other connectors in the circuit. Did you check the NIN circuit to ensure you have the correct connector and pins? Just to rule out the engine ECU being faulty!!

when driving

Do you have the data page for the HYBRID CONTROL ECU which will show gearbox speeds

As above, 12v is very important for the ecu's on starting. The READY light when on means it is ready to drive, flashing - it is starting up from total power off state. You don't need to hold the key in the start position, it is beneficial when the battery is low is to turn the key from off to start in one go. Issues could be the inverter or the combined power steering / gearbox oil pumps are driven by an a/c motor, has failed. Need to get the codes / sub codes read

do you have any sub codes for P3120- xxxx as this will narrow down the fault

You could double check you have the correct pins on the connector, I have had this issue, by checking the good speed sensor in the transmission. Same connector as above but check between pins 12 and 19; Using a Toyota electrical tester, check the resistance between the engine control computer's vehicle side connector D12 (NIN+) terminal and D19 (NIN-) terminal. Reference value: 560-680Ω (20°C) If you get this resistance but nothing on the NOUT pins then you know it is either the sensor or wiring. I had a look at my engine to see if I could see the sensors, but no luck with the inverter cables, hoses and other cables in the way.

This looks to be a transmission issue, check the gearbox oil level, oil hot cycle the shift lever slowly though the whole range and back to Park. Check the transmission oil level with the engine running, top up if necessary with the correct oil, Toyota Genuine CVT Fluid TC. P1825/67 - When the READY lamp is on and the vehicle is traveling at 28 km/h or faster, the secondary pulley speed sensor (NOUT) detects a speed of 300 rpm or less for 2 seconds or more. Wire Harness or Connector Transmission Revolution Sensor Engine Control Computer If you can monitor live transmission data, (S2000 is the Toyota test tool): Inspection Procedure Step 1 S2000 data reading (secondary pulley speed) Connect S2000 to DLC3. Turn the ignition switch ON and read the secondary pulley RPM on the ECU data monitor according to the display screen of the S2000. Reference value: 0 r/min (when stationary) 2600r/min (at constant vehicle speed (approximately 60km/h)) The sensors are underneath the inverter of course!! The resistance can be checked by; Disconnect connector D of the engine control computer. Using a Toyota electrical tester, check the resistance between the engine control computer's vehicle side connector D13 (NOUT+) terminal and D20 (NOUT-) terminal. Reference value: 560-680Ω (20°C) Hope it is just the oil level! rab0716c.pdf

I can't find anything in the manual diagnostics for this issue and why code P1835 is not in the manual. (in the previous post I said "P1820, P1825 and P1835 are referring to transaxle transmission" that should be P1845 not P1835. What are the symptoms when driving? What warning lights come on? Does the gearbox shift gears ok when accelerating? When checking the resistance above was that the harness connector or the position sensor connector? I think it should be the position sensor connector. hdam0480.pdf

If the resistance was high I would check the connectors at the ECU, I will find out the pins on the ecu connector to check out each wire.

P1835, This is not listed in the manual. P1820, P1825 and P1835 are referring to transaxle transmission revolution sensor and oil pressure sensor P3101-548, Abnormal signal received from engine control computer (CVT system abnormality) The hybrid vehicle computer performs fail-safe control based on an abnormality signal from the engine control computer (when the engine control computer detects an abnormality that may affect THS control). C1310-156 IG2 terminal voltage is 10.5V or higher for 1.5 seconds or more, and the traction control disable signal is received for 0.07 seconds or more while communication with the hybrid control computer is active. Hybrid control system (VSC, traction control malfunction). This is a normal fault code when the hybrid computer stops talking to the skid control computer due to a hybrid issue. As I don't think there is a kick down as such, you could check the accelerator pedal connector: Accelerator position sensor resistance check ../../img/a055961.png Use a Toyota electrical tester to measure the resistance between each terminal of the connector. SST 09082-00030 09083-00150 Reference value: Terminal number Reference value 2 (VPA2) ←→ 1 (EP1) 5.0kΩ or less 5 (VPA1) ←→ 3 (EP2) 5.0kΩ or less 4 (VCP1) ←→ 1 (EP1) 1.5-6.0 kΩ 6 (VCP2) ←→ 3 (EP2) 1.5-6.0 kΩ

I do not know, it was just that you were in that area with a mass of wires, something could have been disturbed. Does the replacement head unit support a speed input?

Hi P0500/42 - When the secondary pulley rotation speed is 1000 rpm or more and the SPD signal is not input for 2 seconds or more while driving. The wheel speed pulse signals output from the ABS wheel speed sensors attached to each wheel are converted by the skid control computer ASSY into vehicle speed pulse signals (equivalent to 4 pulses per rotation of the transaxle rotating shaft), which are then output as a vehicle speed signal to the combination meter and input to the engine control computer. There is a speed signal fed into the head unit, from the combination meter, if this wire is connected incorrectly or grounded then the speed signal may be compromised. Originally a grey 5 pin connector connected to the head unit, this has probably been removed now. A Violet colour wire is the speed signal, within the same harness as the reversing pink wire and parking brake switch blue/white wire. Hope this helps