P1738-honda

Question

I have a 2002 honda accord DX. While I was stopped waiting the traffic lights, I felt car was idling rough and the check engine light came on. I took to an auto part store the OBD II scanner showed following codes: P0135 and P1738. I already searched P0135 and found it is O2 sensor but P1738 is second clutch pressure switch. Are they related? Why the check engine light appeared as these two problem came at the same time?
Also, there are two O2 sensors, upstream and downstream, which one to replace or both of them?

Answer 1

HI there

The O2 sensor code is for the upstream O2 sensor or the one BEFORE the catalytic converter.

The other code is for the transmission solenoid. One will not cause the other 

P0135 HONDA - O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 1

Read more: https://www.autocodes.com/p0135_honda.html