P135b code - how to track it down?
 

p135b - Ignition Coil Supply Voltage Bank 2

The car barely runs. It feels like it's running on 4 cylinders which may make sense if Bank 2 isn't getting any voltage. I checked the fuses and they're fine. I'm at a loss of where to look for what. Any suggestions?

So do you have battery voltage on pin 4 of the coil connector (violet/light blue wire)?

Some troubleshooting I found for P135B code possible causes;

Blown Ignition Coil Fuse Ignition
Coil Fuse harness is open or shorted Ignition
Coil Fuse circuit poor electrical connection Faulty Engine Control Module (ECM)

The Engine Control Module monitors the ignition voltage from the fuse to the individual coils. The Diagnostic Trouble Code will set if the ECM detects less than 2.5 V on the ignition coil supply voltage circuit for greater than 313 ms

Are you suggesting a specific coil or just any of them on bank 2? That’s what has me confused. The error is for the whole bank and not a specific coil.

You might check the wires that go around the back of the engine.. I have heard that sometimes they become frayed from rubbing.. not common but could happen.. check the easy ones first

Thanks guys. Figured it out. There was a poor connection between the main fuse block and the harnesses under it. Cleaned up the pins and the problem seems to be solved. Kinda a mystery as to why this is the case. The car has 20k miles and has never even been in the rain. But whatever, it’s running strong again.

so to clean the pins do I just use dielectric grease or how did you do it?

Cleaning may depend on what kind of dirty they are. A little scraping, some cleaner, a rag, emery cloth, etc. But once it's clean then you apply dielectric grease and that should keep it from getting as dirty again.

I have this on my Lt1 with FF Sensor, P135B, just at Titan said its basically running on bank 1. The other code is P0178 FF Sensor circuit low which makes since as the FF sensor picks up a signal from the number 6 coil on the DSX harness. Did you check the fuse for Bank 2 before you found the issue with the pins? Thanks for the heads up on your fix for this issue, I'm looking at the grounds also.

So today Matt tracked down the issue, it was Bank 2 15 amp fuse. He also checked all the FF wiring, nothing cut or pinched that he could see. Pulled the fuse box, check the ECU pinning for FF sensor which has been in the car since 2/2/2022 and has almost 9,000 miles on it. So, check your fuses first if this ever happens, then as OP said check where his issue was also. Trace the wiring for pinched or cuts. Sometimes this shit is just a mystery. Carry a couple extra 15 amp fuses and have fun.