thender

Everybody-

Car is a 2002 3.2 TL. 220k miles.

for the last few months on cold mornings the car will give me trouble. It will act sluggish, the CEL and TCS lights come on, and code P1607 (ECM failure) is posted.

When I drive a block or so, then turn the car off and restart all is fine. It starts and runs fine until the next cold morning.

It only happens when cold (below ~45 degrees) outside. No trouble on other days.

there are a couple threads from folks that had similar behavior but nobody posted about how they resolved it.

Since low voltage can lead to odd errors I replaced the battery but the problem persists.

i have had this happen 7 or 8 times. Only on cold mornings.

i took it to a local Indy Acura/Honda specialist but while they replicated the problem they could not identify a fault.

I’m tempted to just live with it until it occurs more often. Spring is here and we won’t be seeing low temps again until next Fall (I live in SoCal).

anybody have an idea how I can troubleshoot this?

thanks in Advance!


[edit — forgive the typo in the title. “CELP” should have been “CEL”]

zeta

iTrader: (1)

This is what the 2G CL Helms service manual states about P1607, it cannot be much different from your TL:


IMHO, I'd get the PCM replaced if all else checks out, because there is nothing like a 'bad day' when an 'Intermittent failure, system OK at this time' occurs
when you need the car in a hurry.
You don't specify whether you have a TL-P or Type-S, with that said, the PCM's are a dime a dozen on ebay & cheap, just search the OEM part #.
Good Luck.

thender

Awesome reply Zeta — thank you so much for the info.

The car is a basic, (non-S) 3.2 TL.

One dumb question though…. Would I perform the reset on a cold morning (when I would expect the problem)?

Or after encountering the problem and the CEL is lit?

Lastly, do I pull the clock fuse to reset the ECM, or is there a better way?

THANK YOU again for the help.

Saudade

From the FSM:

You can reset the PCM in either of two ways:
• Use the OBD II scan tool or Honda PGM Tester to clear the PCM's memory. See the OBD II scan tool or Honda PGM Tester user's manuals for specific instructions.
• Turn the ignition switch OFF, and remove the No.13 CLOCK BACKUP fuse (7.5A) from the passenger's under-dash fuse/relay box for 10 seconds.

The FSM says to perform the PCM Idle Learn Process after doing this. Honestly I've never done this and have had no issues with idle. However, here it is.

To complete the idle learn procedure, do this:
1. Make sure all electrical items (A/C, audio, rear window defogger, lights, etc.,) are off.
2. Start the engine, and hold it at 3,000 rpm with no load (in Park or neutral) until the radiator fan comes on, or until the engine coolant temperature reaches 194°F (90°C).
3. Let the engine idle for about 5 minutes with the throttle fully closed.

NOTE: If the radiator fan comes on, do not include its running time in the 5 minutes.

zeta

iTrader: (1)

When you restart the car, after driving a block or so, does the CEL stay on when restarting and then the car runs fine?
You can try to reset, on a cold morning, before the CEL is set to see if it aids in diagnosing the issue.
However, that's a lot of work because before you drive you should do the idle relearn, though as mentioned by Saudade, results may vary?
If the P1607 comes on as it sits, while idle relearning, before driving, you may have your answer in regards to needing a substitute ecm/pcm as the attachments mention.

Saudade

So just to clarify, I've disconnected the battery several times to do other work. I've also replaced the battery (separate incident). I've also used my OBD-II scan tool to reset codes after changing O2 sensors. I know it takes a while to clear the readiness monitors (needed to pass smog check here in CA), unless you do the proper drive cycle. Likewise, the Idle Learn procedure likely reduces the time needed to set the proper idle parameters, rather than just driving around for a few days (like I do).

In your case, stick to the procedure as Zeta suggests.

The FSM says:

The idle learn procedure must be done so the PCM can learn the engine idle characteristics. Do the idle learn procedure whenever you do any of these actions:
• Reset the PCM.
• NOTE: Erasing DTCs with the Honda PGM Tester does not require you to do the idle learn procedure.
• Remove the battery or disconnect its terminals.
• Remove the PCM or disconnect its connectors.
• Remove the driver's or passenger's under-dash fuse/relay box.
• Remove the BATTERY (120A) fuse from the underhood fuse/relay box.
• Remove the BACK-UP, ACC (40A) fuse from the under-hood fuse/relay box.
• Remove the No. 13 CLOCK, BACK-UP (7.5A) fuse from the passenger's under-dash fuse/relay box.
• Remove the PGM-FI main relay.
• Disconnect the starter cable terminal from the underhood fuse/relay box.
• Disconnect the connectors between engine wire harness and left engine compartment wire harness.
• Disconnect the connectors between the dashboard wire harness A and the dashboard wire harness B.
• Disconnect the ground terminals, G1, G2, G101, and G102.

thender

Greetings again everyone.

I completed the ECM reset and idle-learn procedures on Tuesday.

the car seemed to idle smoother.

i drove it around for 10 miles or so, shut it down and then verified no codes were posted.

I left it outside overnight. It was about 45 deg or so.

Wednesday morning I checked the codes and it posted P-1607 even BEFORE I started the car.

So it seems that the ECM is failing it’s power-on self test or something similar.

So I will probably consult with my local Indy Honda/Acura shop about the next steps which probably include replacing the ECU
unless they have a better idea.

thanks again to all of you for your stellar posts. I really appreciate the help.

JuicyJ

I really hope you get it fixed.

One thing to keep in mind about our 20+ year old cars, they are 20+ years old!
And, unfortunately, the early 2000's was a difficult time for the electronics manufacturing industry as they navigated new environmental legislation like RoHS and dealt with other manufacturing issues like short-lived capacitors, lead-free solder and tin whiskers.

Those who had a 1st or 2nd gen XBOX are familiar with failing capacitors, or RRoD...Red Ring of Death.

The ECM, along with other items in our cars, are from this era and are not getting any younger. I will say, (I work in the electronics industry) that the Honda stuff seems to have been built better than other items. But, this stuff can definitely die from old age, and every generation of new models gets more of it.

zeta

iTrader: (1)

Check out the website below and the services they offer.
Since you live in California you would need a KL ECU:

37820-P8E-L62 ECU with PROGRAMMING - VIN & Security | Acura CL TL | ECM PCM Engine Control Computer OEM (modulemechanics.com)

thender

Very true and something to ponder.

Mechanically my car is in phenomenal shape; runs well, doesn’t burn oil, and interior is in good shape.

It used to be the engine that was the weak link; now it is the electronics.

thender

interesting site Zeta; worth pursuing. I will be sure the shop is aware of this option.