I have a manual ‘13 fit with about 150K. It was feeling sluggish and then 3 weeks ago it lost power, smoked a little, and I pulled off and towed it to the dealer. They diagnosed and replaced as follows

Cause: code p0203 cylinder number 3 injector circuitopen/malfunction tested resistance at injector should bebetween 10 and 13 ohms got 0 injector is faulty
Correction: REPLACED INJECTOR
HP16450-RNA-A01 INJECTOR 16450.

I thought I was lucky to get away with $300.

Yesterday it lost power again and my husband drove it about 10 miles home.

Now the dealer says it needs a new computer for $1700

Cause: CODES FOR #3 MISFIRE. #3 FUEL INJECTOR CIRCUIT MALFUNCTION.
Correction: PULLED #3 PLUG AND FOUND SOAKED IN FUEL. #3 INJECTORSTICKING OPEN FLOODING CYLINDER WITH FUEL. PCM IS BADGROUNDING OUT INJECTOR CAUSING IT TO STAY OPEN ALL THE TIME.

Dealer says that the first injector really was bad but this seems like too much of a coincidence.

Thoughts are welcome.

 

If the new injector retains the fault of the failed one, you can assume that you didn't have a bad injector..
The problem could be in your car's computer, but saying a car has computer trouble is a big claim because the computer is the end of the line in electrical diagnostics, which insinuates that everything between the injectors and it is operating properly. I'll take a look at the manual and see if there's a relay that could cause a stuck open fault in an injector..

 

Also, should have mentioned that the computer part is on indefinite back order, which is a bigger bummer!

 

I have to agree with the previous poster. They changed the injector and now want to change the entire computer? Check the wiring and the connections between the computer and the injector that is malfunctioning. There is certainly no guarantee that a new computer will solve the problem. It may and it may not! Best of luck Clay

 

In fact, why would only the same injector fail because of the computer? What about all the others? The computer may have a separate wire for injector 3 but the internal computer circuit should be the same right? Only number 3 points away from the computer in my opinion. Clay

 

I'm not too stoked about what I found, but it's not completely definitive. What I'll be adding on here is 3 pages of troubleshooting for the code that you got (which does result in swapping the computer,) and two pages of wiring diagrams showing how power flows from the battery to a single EFI relay, then to all four injectors. This means that if the fault were in the relay, all four injectors would have the same issue. To trace the injector wiring for yourself, start at the D in the middle of the first page, follow it back to the ECM and PGM-FI Main Relay 1, then two fuses (the tilde squiggle lines) before arriving at the battery. Then go to the next page and see line D head to all 4 injectors.

Since your injector is always on it is possible that the grounding wire for your #3 injector has been damaged and is grounding out before it reaches the relay/ecm. I came up with an idea for testing it.. You could use a multimeter to figure out if you have a break in the wire. with the suspect injector's electrical connector unplugged (at the injector), turn the ignition to on (II) and stick the positive and negative probes into the connector. If it shows voltage, it's grounded out before reaching the computer.. It shouldn't have ground until the car is fully started, and then only intermittently when the injector is being activated to spray fuel. Be sure to try sticking the probes in both holes like.. both ways. I'm not sure which is positive n which is negative.

Man, it's been years since I last tried to understand a schematic. I've forgotten so much

If it doesn't have voltage.. I think you may have an ECM issue..OR need a software update from the dealer.. I believe I read that somewhere..

Edit edit: the reasoning behind the test here is that if the fault is in the ECM, it wouldn't manifest when the ignition is only in the on (II) position. I may be mistaken.. Hey resident big-brains, does this make sense?

 

Good evening I have just been going through the same issue with my injectors I had one injector short to ground when this happens it can fry the transistor in the ecu. I have a guy who can relplace the transistors cheap to save you buying a new ecm, it happened to me twice. The first time I replaced one injector a scrap yard ecu then had Honda program it, the second time I replaced all the injectors and had the original ecu programmed again after it was repaired by a local electronics shop for pretty cheap. This failure is quite common over seas and is just starting to become a thing here, I will post a link to the electrical repair done to the ecm. Maybe you can find someone local to do yours.

here is a link to the video and the failure area as well as how to check it.

these faults originate in the injector which cause a failure at the ecm. You must replace all your injectors before repairing the ecm or it will happen again. I believe you should have 7.3vish at the injector clip with ignition on, if your are reading 12v the injector has failed and fried the transistor in the ecm. All good
injectors should read around 10.3ohms if I’m not mistaken.

 

I also have the chips in my possession to repair the ecm if you need it done, it will save you a BOAT load of time and money. Just trust me measure the resistance of the injectors and the voltage at the clips, you will see the failure. Make sure you replace them all, I made that mistake the first time and only did one.

 

@cutsheal5 That's really cool! I'm curious, have you tested the new injectors for resistance since replacing them? Couple years back I was troubleshooting air conditioning not working and the service manual brought me to the field coil which came in at around 4.2 ohms, but was supposed to be 3.6 or so at maximum. I ordered a new one from honda because in addition to the continuity reading I noticed a physical defect in the surface that looked like someone pressed a torch-heated pen tip into the face of the thing. tested out the new one on the parts counter, came in at 4.1. my fault wound up being a rat bitten wire hidden around the front right headlight.

I guess my point being that I'm uncertain the injectors are the cause of the fault because I don't entirely trust specs. I'll go test resistance on my injectors so i can post numbers, and if you could test yours that'd be tight. The computer repair is a super slick option that should be taken advantage of if the problem winds up being there (sounds likely.)

 

I believe I have the old injectors including one new one I can test the resistance on no problem. But when you find the bad one you will know it will be way different, the voltage at the injector clips will show the same thing.

 

here is my three good injectors I threw out the bad one, it was reading open. If you check the injector clips for the injector that tests bad you should get a reading of 12v or 0 I forget but this will show you the transistor is bad. All good ones will read around 7.4 at ignition on engine off.

 

Nice work!

Getting at the #3 injector for voltage/resistance testing can be done on vehicle. Shown here with my pointer fingers on each side of the injector's connector applying inward pressure to disconnect it.



My junky old Innova 3320 read semi-steady at 12.9 on injector 1, but I did have varying readings with it.

The Midtronics PDF40 that I was gifted performed with far more confidence.

10.5 ohms on #3, 10.7 on #1


With the key in the on (II) position, I got 7.3 volts DC. showing as negative, guess I had them reversed.

@cutsheal5 Looks like your method could successfully verify if the ECU has a fault! And like my method was bogus 🥲
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@cutsheal5 Looks like your method could successfully verify if the ECU has a fault! And like my method was bogus 🥲
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Yes it works well I’ve done it twice now i would suggest testing them all you will find the fault in the ecu. I also figured out what chips were bad in the ecu, I just don’t have the tools to replace them myself. You can order the chips on eBay for cheap, splitting the case of the ecu is the hard part..

I should also note the injectors fail and take out the chips in the ecu because there is no protection on the circuit so the chips are sacrificial. Most people would change the injector and think it’s fixed but it won’t, the dealer likely moved the injectors around like I did and screwed up more than one chip, so even if you replace the ecu you might have another injector go bad prematurely now if you didn’t replace them all and take out that new ecu. The best corse of action is replace all the injectors and the chips all in it was like $375.00 Canadian so that’s like $15.00 American for four injectors the chips and the cost to replace them.

 

$15 american
I hope OP comes back to this. Say, did you figure out the chips on the board by looking through a video or by looking for discoloration on the board?

 

I actually figured it out by getting a pinout diagram for the ecu the followed back from the pins to the chips, then I tested them and one and two were reading different from three and four. I knew one and two had an issue, after I did more digging I found out what the chip was after using a magnifying glass to get the number off them, I found them on eBay and took a gamble on the local electronics repair guy to replace them who ended up being extremely knowledgeable and he’s the one who made the video. So that’s actually my ECU in the video he is repairing.

 

Hello! I am the OP and I have no idea what you all are talking about, but I am going to share this thread with the service tech at the dealer. As of last week, the ECM had been back ordered until Oct 5 and with no loaner absolve, that was going to cost me on a rental and then the heft repair. Armed with the confidence of having read your posts, I pushed him to figure out if he could get/use a salvage ECM. Initially he said no, they had to be dealer programmed to the VIN, but I asked him to double check and he came back and said they can, it’s $200-300, and it will be in on Tuesday.

Thanks so much for all the research and suggestions!

 

good morning, a used ecu for these cars are extremely cheap. If they haven’t they should test all the injectors again and replace as needed or it will cost you another ecu. I would recommend replacing them all before you replace the ecu.

 

Did you ever get this sorted out?

 

Could a moderator please pin this post to the top of the page it will be extremely helpful for people going forward. It appears this issue is happening more often.