Toyota first introduced the hybrid version of the RAV4 SUV in 2016. Prior to that the RAV was only available with High Voltage as a pure EV. Earthling has worked on them all: the old school EVs from 1997-2003, the ones produced in partnership with Tesla from 2012-2015, as well as the newest hybrid ones.
Fortunately the hybrid models are still fairly young in hybrid terms (less than 10 years old) and by the time Toyota offered the hybrid powertrain to the RAV, they’d pretty much mastered the platform. Thus RAV4 hybrids are extremely robust: while we happily service them no matter what they need, they typically aren’t having hybrid issues at this time.
So we were naturally curious when we saw a 2016 RAV4 Hybrid this month with the hybrid warning alert on the center display “Hybrid System Malfunction”. The only trouble code stored was in the Hybrid ECU (Electronic Control Unit):
P0A2D Drive motor A temperature sensor circuit
When the car sets a code it typically includes a snapshot of the data stream from the computer that detected it (officially known as “freeze frame”) and in this case the readings for Drive Motor A (the big electric motor in the transmission, also known as the “traction motor” or MG2), showed negative 40 degrees Celsius, an implausible value and a dead giveaway that the electric circuit was broken (referred to as “open”) causing the computer to lose connection with the temperature sensor.
The drive motor A sensor on the RAV4 Hybrid is located under the engine air filter box on the top of the transmission. Upon removal we spotted rodent droppings and other signs of occupancy. It took a second to notice that the wiring to the top of the temp sensor connector was completely eaten off, cleanly at the top of the connector all the way back to the trunk of the main engine compartment wiring harness! Evidently this one section is particularly tasty, in addition to providing important information to the hybrid system!
See photos before and after repair.
The fix was repairing the wiring harness and consulting the owner on laying traps wherever the vehicle is typically parked. Note proper solder seal and heat shrink, and factory equivalent loom sheathing. This repair cost a half hour of labor in addition to the standard initial diagnostic inspection, out-the-door with no more codes or warning messages for $330.
(Note that the Toyota dealer will often refuse to repair electrical wiring and require the entire harness to be replaced instead. The difference in the cost can be thousands of dollars. It’s not because they’re mean or incompetent: it’s an extra prudent policy stipulated by the manufacturer. Another benefit of having independent professionals diagnose and repair your Toyota.)
When you come to Earthling for warning lights (or any issue!) we will document all the diagnostic findings and any necessary repairs with full transparency. We’re always happy to make you happy when the job turns out to be a simple one!
Text or call us anytime, 415-875-9030, or you can book an initial diagnostic inspection online 24/7.
