Tcb816

Hello everyone, I'm the second owner of a 2013 G37 with 116,000 miles. I bought it and 2019 with 53,000 miles and it has been a fantastic car. I've maintained it carefully.

Last week it went into limp mode. I took it to my mechanic and here are his notes:

"PO720 - speed sensor circuit
Tech clear codes. Upon further inspection and testing fault code: P1721 vss circuit.
During road test and testing, transmission has slip on 3-4 shift as well. Due to fault P1721 transmission will need TCM/valve body, harness and output speed sensor replaced.
However, due to slippage on 3-4 shift, tech recommends rebuild or replace transmission. Recommend take to transmission shop for repair as the transmission is discontinued from the dealer and we are unable to locate a rebuilt unit."

Just wanted to get everyone's thoughts and opinions on next steps.

dkmura

Welcome and it sounds like your tech did a good job of tracing a diagnostic trail. When was the tranny last serviced? Has an ATF change ever been done?

Tcb816

Thanks for the reply. Yes, an ATF was done at 90k. I'm not sure what the previous owner did or didn't do.

I'm reading on other threads that i should try cleaning the MAF sensors and throttle body. Based on the diagnostics so far, is that even worth trying?