Hello everyone, kinda new here, so thanks for the tolerance. I just acquired a 2002 Accord with a 3.0l V6, but it has significant issues and the history is unclear but it is obvious that nothing good has been done on this car. So.... the possibilities are Endless.

The Car is currently throwing the following codes: P1607, P0108, P0118, P0123, P0113, P1498. The symptoms are, the temp gauge does not work, the car will not raise the RPM above @2700, and the car will not shift out of 1st gear. (if placed in D3 or D4, the car may not move at all). The car maxes out at about 15 mph.

I have read here in the forum that the ECU/PCM does not typically go bad, but this seems like the obvious choice concerning what I am seeing. Are there other items i should consider? There seems to be some 'hackery' that occured with the battery cable, so no idea if a previous mech did something to short stuff out (there is a household lamp cable being used now as a fusible link, so chances are good he screwed up). I have had the car a matter of hours, so not too much else has been done. Previous gent gave up on the car after 3 weeks.

ECU seems like logical step to me, but i am also wondering about best way to reprogram the key to work with the new ECU.

Appreciate any thoughts.

 

P0108 - MAP Circuit High Voltage
P0113 - IAT Circuit High Voltage
P0118 - ECT Circuit High Voltage
P0123 - TPS Circuit High Voltage
P1498 - EGR valve position sensor High Voltage
P1607 - PCM Internal Circuit Malfunction

Fix the hackage, fix any damaged wire harness, put everything back to factory.
Cannot rely on some hacked up wire harness to function correctly. With all the sensors showing high voltage, the harness is probably messed up somewhere.
00+ cars do not have a separate engine to dash harness/sensor system like on the older car. The gauges get data from the PCM directly.

A new PCM might be in order, but don't make that the first thing.
If the 1607 code is real then going through the trouble of replacing the may just be futile if the wiring harness that is hacked up is what killed the PCM in the first place.
If you want to keep the car, fix the damaged wire harness.
Verify ALL applicable grounds and bonding cables are installed.
Then clear the codes and see if the car will run/drive normally.
Transmission functionality greatly depends on engine running condition.
Albeit all those codes will go away after the wire harness has been fixed, except, maybe the 1607 code. But you will still want to fix the wire harness before spending money on a PCM that can be damaged by a bad harness.
Find out as much as you can about the car.
Find out what/why the car was worked on.
Find out why the car had to be worked on.
Even if it seems unrelated to engine(he put in a new stereo system, tires were changed, etc etc) that information will get you pointed in the right direction.

The first thing I would NOT do is put a new PCM into it.

 

Thank you @Mad_Mike. The hackery appears to be between the battery and starter, and ground, etc. Best i can determine, the ground cable may have been damaged in an accident and the previous owner just ran a new cable 'around' stuff. So hopefully an easy fix. (ha, famous last words)

Where is the best place to locate a wiring diagram for this car? Is there a preferred location? Anything free or low cost?

 

check your local junk yard for parts

 

The last question was where to locate a Technical Service Manual (Which I have obtained, thank you Mad Mike). So a junk yard is not the best choice here.

In regards to parts, etc. I will absolutely utilize a local salvage yard, however determining the correct part to replace is a bit of an issue. If the PCM must be replaced, then i must also worry about reprogramming the keys. So the mystery continues.

 

@MAD_MIKE I have fixed the hackery, and it does appear limited to the negative battery cables and grounds. Unfortunately the issue has not been resolved, (nope, i am not that lucky). Same errors in existence.

In researching the cause of the high voltage on the sensors, each of those errors have a potential cause of a bad pcm/ecu. I am seeing no difference in how the car functions. I was only able to spend a limited amount of time this weekend checking, as it was 10 degrees outside and i was working in the rain and snow. My intent is to attempt checking some of these sensors to see what is being supplied and returned. But I am growing more convinced the ecu is bad. What is the best/easiest method to handle changing\reprogramming the keys to work with the new PCM? This is currently my largest concern.

How large was the variation on pcms from other years of 3.0l V6 accords? specifically, would a 99 pcm for a like engined car work for a 2002? I will check model numbers and such on the pcm, but would love to save myself the time if it is a waste.

Thanks!

 

If you can locate a car in the yard and its key that would probably be the cheapest/easiest.
Have an un chipped key cut to your existing lock, then tape the yard PCM key to that with the yard PCM installed. This way the PCM picks up on the chipped key and you should be good.
Biggest difference is 98/99 have a distributor and 00-02 cars were coil on plug which is controlled directly by the PCM.
You would need to verify you are using a PCM that is either for a distributor/wires car or COP car.

 

Although a junk yard is not a tecehnical manual, I often go to look and help visualize in a situation like this. for example, this could help in looking at how the ground cables are installed, the wiring to the starter, and other items like that.

Honda Service manual is here:
Accord - Downloads - Hondahookup.com