Type R Club of America

I just wanted to document my fix for P1457. In case anyone has similar issues. After running through the flowchart for troubleshooting the EVAP controls system, I ended up on "Substitute a know-good ECM and retest. If system/indication goes away, replace the original ECM."
Considering, the ECM for a 98 ITR is hard to find and I didn't have access to another, I opened her up to see if there were any visible issues. With no visible issues, and since the last flow chart test involved the EVAP purge solenoid, I traced the pin involved down to a resistor.
Since, there was no fuse or any protection in between the solenoid, it was pretty obvious the resistor died. They are SENSITIVE! The previous owner, also mentioned that they replaced the solenoid too. Looked up a replacementment and then picked one up on ebay!

NO CODE now!!! WOooohooo!

Wow, this is a truly impressive write up! Electrical troubleshooting is one of my biggest gripes. Not only did you successfully troubleshoot, you soldered a fix on the ECU, and shared the fix with the community.

Oh hell yeah! I have been on a wild goose chase for this code as well . I have two ecus that popped the code . I am going to open mine up now to inspect this .

Did your car do a pending 1456 that turned into 1457?

I am not an electronic expert. To my eye I only see two prongs . Using the camera I can see the third. It certainly doesn’t look like yours. Could anyone chime in on the condition of mine please?

Pardon my ignorance. I see three resistors and the three ponged fuse like device which appears to me was the problem can you specify what actually failed and the part that you replaced it with?

Stin1 wrote:Did your car do a pending 1456 that turned into 1457?

First, fix the cause, which may be a bad relay solenoid. It will keep on killing transistors.

The flow chart will show you how to test each solenoid and check for it holding vacuum.

Then fix the transistor. And yes, that is a transistor, but identify where it failed first.

Let me know if you more insight.

The code I got was a pending 57. I don’t recall if it was a 56 but it looks similar according to manual.

Where is the relay solenoid? I have changed everything electronically except the discontinued fuel tank sensor and another discontinued sensor near the tank . I have resolved this code on a 00 gsr by running the tests and it was the purge. I was asking about the ecu itself & its condition, the part number.

Thank you for your help kind sir .

I meant to say evap purge valve solenoid, and canister vent solenoid. They are kind of like a relays, same concept with magnetizing but they control the flow of air. Maybe I shouldn't call it a relay, ha!. The ECU turns them on and off with a transistor to create a vacuum in tank (stupid emissions, vapor gas bullshit). The pressure sensor is part of it. Hence, when you don't tighten gas cap, it will throw a 1456 code.

1456 deals with the tank side of things, 1457 deals with the front. They both may come to the same conclusion but testing vacuum is important to see what's failing.
But once you identify what's not working. You test that solenoid, and if that's working, you look at ECU. I identified that the solenoid was working then trace the circuit to identify the transistor. Once, Identified, you can use a multimeter to test it. I believe the diode settings. See here: https://www.youtube.com/watch?v=2IkAPU9X33k

The service manual flow chart does show you how to test each and every section but I'm not sure about tank side (1456) . I think they are just sensing negative pressure? I have to look into it. You probably have to vacuum the whole thing.

You can identify the transistor by the markings on the transistor. Yours's look the same as mines, "D1780." Look up SD1780 on eBay. They label them "Honda SD1780 transistor." Alternatively, Digi key or other transistor suppliers. I thought buying from eBay is faster but it's not.

I do have a spare if you want it.

And sorry if I didn't explain it very well. I am happy to get on a conference call to help.

Thx