Vehicle data: 12/07 Honda Accord, 2.4 L DOHC, auto transmission.

Approximately 2 or 3 times a week there will be extended cranking time before firing. These extended times are about 3 or 4 times normal cranking time before firing. With some of these extended cranking times the yellow engine light comes on. This light will go out after a day or 2.

On 2 occasions the car went into "limp home mode". In this condition the car would struggle to achieve 40 km/h and have very little power. This condition occurred the first time after extended cranking. The 2nd occasion was whilst driving: the engine started normally but at about 30 km/h power was lost and a maximum speed of 30 to 40 km/h was all that could be achieved.

Diagnostic scan results: P0339 CKP sensor circuit intermittent interruption; P0302 misfire #2 cylinder; P0303 misfire #3 cylinder; P0300 random misfire; anti-lock brake code- 83-13 ECM/PCM relation failure.

In an attempt to solve this issue I have changed the CKP sensor, changed the in tank fuel filter, drained and cleaned the fuel tank and tested fuel pressure. As codes were thrown up for number 2 and number 3 cylinders, coils and plugs were swapped with 1 and 4 cylinders. All these measures have not resolved the extended cranking times. And we are waiting for the vehicle to go into its 3rd "limp home mode".

After this work was carried out I consulted a Honda dealer with vehicle specific diagnostics. The vehicle was off the road at the dealer for a week and a half with no resolution as the fault conditions that existed in the vehicle on arrival disappeared after about 4 days and for the remaining time the vehicle functioned normally. The Honda technician was working through a checklist and when that checklist failed to fix the problem the next stage was to get from Honda Australia a test ECU. But they could not tell me when this would be available and didn't seem very interested in pursuing the problem further. They said if I brought the vehicle back they could only do what they had done previously that was unsuccessful. In addition to that they seem to blame the age of the vehicle and what put me off even further was when they said I wasn't a regular customer. So I felt quite abandoned.

During their investigation they failed to: check the CKP sensor wiring for continuity back to the ECU; did not check the waveform or the amplitude of the hall effect CKP sensor output nor did they check the plug connections at the back of the ECU. That seems to me to be a major failure in diagnostics given the problem was intermittent.

At this stage I am wondering whether there are any other sensors that combine with the CKP sensor to get the engine to fire normally. There could be a deterioration or an intermittent fault on one or more of these.

I really hope you can shed some light on this problem.

John

 

Jt could be an intermittent wiring fault. Only way to test is to check for continuity of wiring and stress wiring manually looking for a fault to occur. Finding fault can be tedious. There are fault tracing tools to assist (Loadpro) finding fault location.

good luck

 

Thanks TexasHonda,
I have been thinking about running parallel wiring from the CKP sensor to the ECU. But firstly I wanted to ask whether there could be any other sensors contributing to the fault.

 

Problem Solved

I hope I have a solution for others.
Continuing from my original post, I
spent a month or two logging the battery voltage on starting. I recorded
the lowest voltage for each time the vehicle started. I am away from
home at the moment and unable to consult my records but my recollection
is that when the battery voltage on starting was depressed below 9 V the
ECU did not like it. This condition gave rise to the ECU going into limp
home mode.

I was so fed up with the Honda dealership that I complained to Honda
Australia. What really annoyed me was that I could not talk to any of
their technical personnel directly. The only option I had was to take it
to another dealership or back to the same dealership. I opted to take it
back to the same dealership because I did not want to start from square
one all over again.

When Honda Australia's technical support were contacted by the
dealership the first question they asked was: "has the starter motor
been changed?". Well guess what, I had changed the starter motor to
third party one and not a genuine Honda one purely because the Honda one
was twice the price of third party one. Bad choice. The difference
between the two was that the third party one was a direct drive rather
than a geared drive and drew 1.75 kW on starting. This is what was
depressing the battery voltage so much.

Once the starter motor was changed to a genuine starter motor the
problem was resolved.

This little exercise cost is about $2000 in parts, labour and a hire
vehicle for the week and 1/2 that the vehicles at the dealership in the
first instance.

I hope this has been helpful. It is extremely difficult to get high
quality technical knowledge in dealerships these days.

 

That's interesting... I would have not expected the motor to be that much different if you have simply said "replaced the starter". I haven't come across an aftermarket starter that was so different in actual architecture.

And thanks for coming back! It's too often that we never hear the rest of the story.

 

im having the exact same problem on my 2008 Honda Accord. I also changed the starter about 6 years ago to a after market one (auto zone) and about 8 months ago I started getting the check engine light and now recently it's going into limp mode and all the other stuff you described. How is the fix going for you. Have you had any trouble after you changed the starter. I'm hoping mine is as easy as yours.

 

First thing - have you measured the voltage during cranking? If it drops down below about 9v like his did, then you still need to see whether the aftermarket starter is causing it, or if the battery is simply getting weak. Since it took 5 or 6 years for this to show up, it seems likely to be the battery. It can just as well be loose/dirty/corroded connections on the big cables from battery to ground & to starter. Clean them up & tighten properly before throwing parts at it.

He measured the starter power at 1.75 kW which is close to 200 A (based on 9v). That's a lot of current & probably above the capacity of an inexpensive multimeter. Do you have a way to measure that? Its above the capacity of my Fluke 179 so you'll probably want some kind of clamp-around induction coil for that.

An alternative is to have the battery checked out at a place like Autozone to see if its getting weak.