Limp mode 2018 Acura TLX
Car only acts up under heavy load on accel. No active misfires but will throw the P0303 code (blinking MIL) and then goes into limp mode. I searched for TSBs and Identifix. I couldn't find any protocols for what would cause limp mode. Any help is appreciated.
I had similar on a Honda, Try doing a crankshaft relearn.
Good idea! I just tried it, test drove it… same thing :(
Could just be a bad coil pack or plug. Switch one with another. Any cylinder deactivation should produce a limp mode.
Its highly doubt it is a misfire. It goes into limp mode. Plus, I already tried swapping coils. I think something very odd is going on
Doesnt matter if its a real misfire or not, if the PCM perceives a misfire it will go into limp mode. Id try to figure out why its setting the misfire code….
Thats an odd PCM strategy. I've never heard of a single cylinder misfire causing limp mode. Especially for a Honda. Do you work for Honda?
Its a 2018. Many things have changed in the last few years. If the limp happens only after P0303 sets then seems like the P0303 is the cause. I think your overthinking it. Not saying that to be cocky or demeaning. Just to encourage.
Nate- I dont work for Honda. Im just a very good, well informed diag tech.(who still stumbles occasionally) The strategy has been in place for the better part of 15 years with Honda products. Ive experienced it more than a few times…
My old 2009 Camry had an intermittent #1 injector. It would misfire terribly, flash the check engine light, then run on only a couple of cylinders! (limp home) There! Now you've heard about it! Peace!
The timing chain tensioners are junk is it making any noise ?
No timing chain noise. I dont think it is mechanical because I can clear the codes and its fine again.
The P0303 ia causing the limp mode. Diag the P0303.
Prodemand DTC discription says a type 1 misfire “17-89 misfires per 200 RPM” will cause the “high speed fueling” be shut down from the PCM and sets a pending DTC until a second drive cycle which sets a permanent DTC, seems this will only affect higher engine RPM events.
inspect #3 spark plug. Swap #3 plug with one from a different cylinder and see if the misfire changes cylinders. Check map voltage at idle, ac off as well as any other loads off and in park. Make sure its not in limp mode. Should be .85v if it is .9 or higher or if voltage is fluctuating, check for tight exhaust valves. Also try performing af cylinder balance test to see if you have an injector…
Had an accord with IMA. Similar issue however, pulled one of the back coils and it was oil saturated, it actually killed the coil. Fixed the leak (pinched plug well gasket) and new coil. No misfire now, but threw p0303 again and would flash the CEL on heavy load. It ran great with no counts in mode 6. I found there was a software update for that exact issue. Customer stated it has done that…
Hello Nate, If you have the capability, run an in cylinder pressure test and post your findings. Do the effected cylinder, then do a known good one for comparison. Flashing MIL then goes into limp mode is the computer trying to prevent CAT damage from a perceived dead cylinder issue.
I would swap spark plug, ignition coil and injector of cylinder 3. Also check compression of the cylinder 3. Internal faults in solenoids causes limp. I suspect either ignition coil or injector are have internal fault when under load. Resistance check, and compare to known good ones
Any chance we are having a valve adjustment issue like on older models where valve seat sinks slightly into head and you get misfires you cannot feel ?
This is what I am suspecting at the moment. Although, typically, when you have tight valves you will feel a misfire on a cold start, not heavy load.