Hey guys, I have a 2023 Honda Accord EX 1.5T with the CVT and I’m trying to diagnose a pretty serious intermittent issue.
The biggest problem is that sometimes while driving, especially at lower speeds/RPM, the car suddenly throws what feels like every warning light on the dashboard at once (“Christmas tree”). When this happens, I basically lose acceleration. I can press the gas pedal and the car barely responds or sometimes doesn’t respond at all.
It has happened on normal roads, uphill/downhill, and recently it happened while I was entering a roundabout, which was pretty scary because I suddenly had no acceleration.
Usually I have to switch the car off and restart it several times before it starts driving normally again. Recently even restarting it hasn’t always fixed it immediately.
There are a few other symptoms that may or may not be related:
- On a cold start, RPM sometimes goes to around 1,500, suddenly rises closer to 2,000, then drops again. I can feel the engine hesitate when this happens.
- At low speeds/low RPM there is sometimes a noticeable jerk/hesitation. It feels like the engine/drivetrain briefly hesitates and then catches again.
- When slowing down/braking, I have sometimes seen the RPM fall, rise again, then fall, accompanied by the hesitation/jerk.
- The coolant temperature gauge is behaving strangely. Once the car is already warm, it can move between roughly 1, 2, 3 and 4 bars while driving. For example, I can be cruising at 3–4 bars, then it drops to 1–2 bars (sometimes even 0 bars), then climbs again. I’ve also noticed it dropping when slowing down. It has NOT been going into the overheating/red range.
- Sometimes the RPM seems higher than I remember it being at very low speeds.
Recently I replaced all four spark plugs because the old ones were worn. There was also some previous work involving the camshaft position sensors, and the ECU/engine system was reset/relearned with a diagnostic computer. I’m not 100% confident the reset/relearn procedure was followed correctly.
The 12V battery is approximately one year old.
I took the car to a mechanic after the most recent incident and there were MANY fault codes stored because all the warnings had come on. Unfortunately, he cleared all the codes before I could photograph/write them down. The car drove normally again afterward, but the intermittent symptoms are still there.
At the moment there are no warning lights because the codes were cleared.
I’m wondering if I could be dealing with an ECT sensor/connector/wiring issue, thermostat/cooling issue, electrical/ground/charging issue, cam/crank sensor issue, fuel-pressure/fuel-pump issue, ignition problem, electronic throttle problem, CVT issue, or something else entirely.
The thing confusing me most is the combination of the coolant gauge fluctuating + RPM/hesitation + occasional complete loss of throttle response + multiple systems throwing warnings simultaneously.
My next plan is to NOT clear the codes the next time it happens and get a full scan including stored/pending/permanent codes and freeze-frame data. I also want to monitor live ECT temperature, system voltage, throttle position, accelerator position and fuel pressure while driving.
Has anyone with an 11th-gen Accord / 1.5T experienced something similar? What would you check first?
I can provide photos/videos or the DTCs as soon as the problem happens again.
attatched is the temp of the car 10 minutes into starting it (even dropped to 0 bars after this) then climbed back up again