Kipper-Fish

1992 Honda Civic EXV 1.6 litre 4-cyl VTEC Engine, Automatic Transmission, Air Bags (SRS)

Check Engine Light (CEL) always on.
Engine cranks but will not start.

Battery, fues under hood / dash, Main Relay, fuel, spark all good.
No 5v voltage at MAP sensor.
Suspect faulty ECU ???

When ignition ON, CEL is lit, there is intermittent clicking (energizing) at the Shift Lock solenoid located below and adjacent to the gear shift lever. This occurs whether in P or N.

Can any reader advise as to what might be causing the solenoid to activate even before the engine is started and the brake pedal pressed?

Thanks for your assistance,
Robert
Surrey, BC, Canada.

Kipper-Fish

To further assist readers to help me, additional information here:

When ignition key is switched on, the Shift Lock solenoid at the A/T gear shift lever is still being intermittently activated, confirmed by sound and sight.

CEL remains lit.

New information is that when engine cranks, there in NO clicking at the fuel injectors and NO battery power at their terminals.

Are these related somehow? Does this confirm that an expensive ECU is dead or failing?

With much appreciation,

Robert
Surrey, BC, Canada.

Hanmin

you write like a computer, but its very informative and easy to read. What cel are you throwing? https://honda-tech.com/zerothread/1901557

Kipper-Fish

I can not locate a blue or grey 2-pin Service Check Connector. There is only a single 4-wire green, soft plastic connector under the dash, above the ECU on the passenger side.

I'm advised by dealership that this 1992 1.6L 4-cyl Civic EXV VTEC engine requires a "special tool" to activate diagnostic mode and extract error codes on a hand-held reader via this green connector. Is this correct?

Anyways, if the battery has been removed, recharged overnight and reconnected all without another successful engine start, would the ECU have had opportunity or time to generate and store new codes?

Robert

94EG8

Its there, but it can be difficult to locate, if the car has never been checked for codes before there will be a 3 wire connector and the 2 wire service check connector in a green rubber cover, see picture below.



If by special tool they meant an unfolded paper clip then yes. You simply jump the service check connector and count the flashes, there a long flashes (signifies a 10) and short flashes (signifies a 1) Its sort a visual morse code. You will be hard pressed tto find anyone with a handheld reader capable of reading OBD1 codes, save for possibly the dealership.

Depending on the code and whether or not you've turned the key to accessory then yes. If it were me I would check the following:

-Thermostat ground, located on the thermostat housing on the back of the engine, follow the lower radiator hose to where it meets the block to find it. If this ground is bad the car can exhibit the symptoms of a bad ECU.
-shift interlock relay, blue box bolted to the inside of the firewall where the clutch pedal would have gone if the car were a manual.

If neither of those helps you try another ECU, it needs to be an automatic P28 from any automatic '92 - '95 EX-V Sedan or a '93 - '95 Si coupe.

Kipper-Fish

Thanks for the photo of the green connector at the ECU.

I have just been down to the car and indeed, there are actually two(2) connectors INSIDE the green cover. I was able to remove the smaller two wire SCC a.k.a. jumper plug.

ECU ground previously checked and good.

Will now check for codes, check blue Interlock Relay before switching out ECU.

Thank you for a most useful post.

Cheers,
Robert

Kipper-Fish

The problem of engine cranking and not starting has been solved with a replacement ECU . The engine started on first crank.

Removed the Gear Shift Position Indicator switch. The slider and it's contacts are well worn and very greasy. Cleaned with acetone, broke off the retaining lugs so face plate could press deeper into box and retained by zap-straps. The intermittent clicking of the Shift Lock solenoid has now stopped. All position indicator lights, including P, are working as normal.

The Shift Interlock system is now preventing the gear lever from being pulled out of P when engine running and brake pedal depressed. Both Key Lock and Shift Lock solenoids test good. Key Lock retains key when not in P. All fuses and grounds are good. Brake lights and switch are good.

How can I test the Shift Interlock Control under the dash?

(It's proving impossible to remove from its bracket. Any tips please?)

Thanks in advance for any additional assistance / advice offered.

Robert
Surrey, BC, Canada.

94EG8

Any possible chance the new ECU you got is from a manual civic? '92 - '95 civic automatic transmissions are controlled entirely through the ECU.


Modified by 94EG8 at 7:32 PM 11/14/2008

Kipper-Fish

A very good point bearing in mind that the Shift Lock solenoid was intermitently clicking away while the older faulty ECU was still in the car.

The part number on the previous ECU was as follows:
37820 - P28 - C50.

The replacement ECU has a hand written, permanent marker inscription as follows:
'92 CIVIC EX

i.e. no mention of whether it is for standard or automatic.

The part number on the replacement ECU is as follows:
33920 - P28 - C51

Is there a way to use this latter number to verify its suitability for an automatic transmission?

94EG8

The P28 tells you that the ECU is for a D16Z6 (1.6L SOHC Vtec engine) the 3 digits after the P28 tells us the following"
C -> Canada, ECU was designated for the canadian market
5 -> A 5, 7, or 9 generally designates an automatic ECU, a ) is typically used to designate a manual.
1 -> revision number

So in other words its the right ECU. You say you checked the brake light switch, is the rubber piece that actually pushes the switch still in place? and as another test, do you have brake lights when the brake pedal is depressed?

Kipper-Fish

Thank you for the breakdown and explanation of the last two ECU part numbers, especially the P28 - C51.

I then followed your lead and looked up the first part i.e. the prefix of the ECU part number and discovered that:
37820 is for Honda ECUs
33920 is for Suzuki ECUs

I find Suzuki ECUs listed with part numbers something like:
33920-XXXXX

I can not find a Suzuki ECU with a part number:
33920-P28-C51

This part number seems to be a hybrid of the two different manufacturers. Does this make any sense to you?

Yes, the brake switch is complete and the brake lights do work.

Looking forward to your reply with much appreciation.

Robert,
Surrey, BC, Canada.

94EG8

No, it doesn't make any sense to me either. All my information states that 37820 is *always* honda's part number of the ECU. Any chance you can post a picture of the sticker on the side of the ECU? Honestly i'm as confused about this part number thing as you are.

The greasy part is perfectly normal. They were greased at the factory. So is the horn shoe on non SRS hondas

I'm not entirely sure how to test the unit, I checked mitchell on demand, and there are test for every other part of the interlock system, except for the interlock control unit. Check fuse #15 under the dash btw. If its good i'd try to borrow an other interlock control module (it can come from any automatic '92 - '95 civic) Its probably easier to remove it bracket and all. They will come off the bracket though, It seems to me theres a tab you need to push in to get it to slide off the bracket.

Kipper-Fish

I have just inspected the actual side panel on the replacement ECU in the Civic.

I see with utter disbelief that the part number on the ECU sticker actually reads:
37820-P28-Cxx
764606401

The Cxx means that although the C can easily be seen, the last two digits have been deliberately scratched out. They can not be read.

No need to take a photo of this unless you would want to see the bar-code and that appears to be scratched out in places as well.

The part number for this ECU that I previously gave to you (and probabaly wasted a whole bunch of your time with) was being read off the seller's invoice to me and I repeat it here again for you:
33920-P28-C51

Clearly things are not as they are meant to be. I will inquire from the seller as to why his invoice is different from the actual ECU.

In the meantime, does the second number 764606401 tell us anything?

The car was driven all night without problem. Seems that, except for the Shift Lock issue, all is good.

Robert,
Surrey, BC, Canada.

94EG8

It doesn't tell me anything. It might mean something to someone, but not me.

In terms of actually IDing the ECU, take a look at the pic below, if you take the cover off you should be able to tell if its automatic or manual (make sure you use a screwdriver that fits well in the screw heads holding the cover on as they are easy to strip.) Also if you look at the ECU plugs on the inside of the ECU there should be another sticker like the one on the outside of the ECU, I doubt anyone throught to scratch it out.

Kipper-Fish

Where do you get all this stuff? It's so very useful to a novice like myself.

I have removed the ECU from the car, opened it and inspected it as per your two suggestions.

1) There is in fact an unblemished, perfect sticker inside the unit and it reads:

37820-P28-C01

From this part number I deduct that this ECU is intended for the Canadian market, that it is intended for use with a manual / standard transmission and that it is Rev.1 As such, it is the incorrect ECU for my daughter's car.

2) By comparison with your photograph above, it is very evident that the two components inside the circle, as indicated by the pointed fingers, are not present. This further confirms that this particular ECU is intended for a 5-speed manual transmission. My daughter's car has an automatic transmission.

In this regard, I am still fortunate because the seller of this replacement ECU is a most decent man and I am sure that we'll be able to swop it for the correct unit. Perhaps he'll allow us to use this ECU until the correct replacement becomes available.

And you, Sir, are also a most decent man having provided me with valuable learning as I have trundled my way through the complexities of auto electronics. Thank you most sincerely for sharing with all of us forum members as you do.

Yours sincerely,
Robert
Surrey, BC, Canada.

94EG8

You can thank Katman (another honda-tech member for some of it, such as the picture and his ff-squad website.) The rest of it is the result of doing numerous hybrid engine swaps and some extensive internet searching over the years.


Even if he wont swap it or refund your money, be aware manual P28 ECUs are worth money. They can be reprogramed for just about any OBD1 or OBD2 civic/integra/prelude engine quite easily. I've seen them sell anywhere between $40 - $120 usually around the $80 - $100 area.

Thank you, and you are most welcome.