Abs Code 13, Open Relay Circuit

[Esaus]

Hi!

I have an Toyota corolla that has been sitting for three years. It belonged to a now deceased family member. He had it sittign for 2 years before he passed away. It is a 97 liftback, E110 with the 1.6 liter, 4A-FE engine. I live in Sweden so it is a Left hand drive car. I thought there would be more help to have in an english speaking forum.

When I went to pick up the car a year ago the brakes where stuck and i was barely able to drive it. Ran really rough. I saw that the abs light was on and the Battery was initially dead. It has been sitting for another year. I have started it once in a while and ran it for a while and recharged the Battery until I had time to fix it. I have another car that I'm working on. There were a few problems with the car.

I read the ABS fault codes by inserting a jumper into Tc and E1 and removing the metal jumper in the diagnosis port.

The fault code I get is 13 — Open pump motor relay circuit. Check modulator wiring harness, pump motor wiring harness, pump motor relay circuit and pump motor connector.

I have tried multiple times to reset the code by having the jumper in and pumping the brakes several times within 3 or 5 seconds which I read it somewhere. It hasn't cleared the code. I tried it with and without the metal jumper in place. Is there another way of clearing the codes?

I googled open relay circuit and found references to checking the fuses, relays and wires.

This is what I've done so far:

I tested the black 4 pin relay 88263-14110. I connected the 2 small pins to the Battery and i get a click. I check the continuety in the 2 other pins and i get no continuety when there isn't any voltage applied and continuety when i apply the voltage and hear the click.

The green ABS TRC Relay has 5 pins 88263-24930. I opened it up and tested the two pins that operate the coil and i get a click there aswell. I don't know how to check the rest of the function.

I checked the 50A fuse and it seemed ok. Pain in the ***** to unscrew it from the bottom. I applied contact cleaner to the fuses and relays and their connections. I searched for obvious cable breaks but wasnt able to find any. The harness cable runs under the front metal close to the radiator so i cant really access it to check.

I opened the relay circuit holder and checked the cables. All look clean and without corrosion. When i put the ignition to power i hear clicks coming from the front as it does the abs check. Then the blinking continues.

I removed the windshield water canister and checked the abs modules wires and connections. I removed them and cleaned them with electronic cleaner. I refit everything and tried to reset the codes with the same procedure. I still get the same error.

The ABS modules has the number 44510-12140. I looked at removing the module to have a look at the back of it, but the bolts are in a very hard place and I don't want to remove the brake lines until I've replaced the brakes on the car. Don't want to dry the brake master cylinder to bench bleed the thing.

What should I do to find the source of the problem? What should i test on the connections near the abs module to rule out a cable break?

I have the wiring diagram from a haynes manual but I can't really figure out what to test. Not an electrician.

I don't want to get a new abs module and find out that it was a broken cable after all!

I tried removing the cables on the abs module on the front side and i get error code 11. When i replace it it goes away. The rear connector gives a fast blinking abs light that goes away when i replace it and then i get the 13 code again. I guess the front connector is the relay circuit connector and the rear for the abs ecu.

I would appreciate any help on diagnosing the problem and finding the fault!

I have to replace all the brakes as they are rusted and worn. I welded the exhaust and might have to fix more as i still hear leaks from the front side. I also replaced the oil and filter and will continue the service when I get more parts. It will get new alternator belts, coolant fan temperature sensor )as it overheats and the fan runs when I unplug the sensor), break shoes, brakedrums, pads and rotors, rust repair in back right wheelhouse, There migth be more suprises as i tinker with the car more.

//Esa

[oldcodger]

Cannot help you myself, never worked on the ABS, but just a chance that this ABS pdf from a 2003 model might give you some clues ...?

https://dl.dropboxusercontent.com/u/5285770/_diagnostics%20-%20ABS.zip

Will leave it there for 24hrs

[Esaus]

Thanks!

I'll have a look at it!

[Esaus]

I have checked the pdf. It says the same thing as most of the other documents I've read with some variation.

DTC 13: With IG1 voltage 10V or below during initial check or ABS control, pump motor relay is turned ON, and relay contact is not ON for 0.2 sec. or longer. And describes the source as abs motor relay or the circuit.

Something I found in another document online:

DTC 13/C0273

When any of the following (1 to 2) is detected:

(1) All the following conditions continues for at least 0.2
seconds.
IG1 voltage is between 9.5 and 17.2 V.
During initial check.
ABS, BA, TRAC, and VSC are in operation.
Relay contact is open when the relay is ON.
(2) All the following conditions continues for at least 0.2
seconds.
IG1 voltage is less than 9.5 V.

Relay contact remains open when the relay is ON.

I've checked parts of the cables in the circuit with a multimeter and get continuety from the relays to the switches that go to the abs module. I also have seen voltage over 12 V over the relays when i had the ignition on. I'll try to replace the relay and see if that fixes it. Could be that it malfunctions under load and the voltage in the circuit drops or that it malfunctions in staying open. The Battery has a good charge and the alternator charges well so it isn't that.

Why can't it be something simple as replacing one of the wheel sensors...

[Esaus]

I uploaded an picture of the wiring diagram for the abs circuit from the book i have.

[oldcodger]

Looking at that wiring diagram, I would first test the connector that goes into the abs unit across the positive from the relay and the other side of the motor down to earth. You should see a nominal 12v .

Can you hear the pump running ? ( though not a test I have made)

If your meter has a 10A DC range then you could measure the current to the pump , which is anothere indication it is running normally, though again no idea what the typical current .

If all that seems to be working ok then I would look at top pin on the diagram marked MT just above the pump motor, to me it looks like a feedback resistor to the control unit, so if that resistor/circuitry was faulty, even with a good pump, the control unit would still give a fault.

If you cannot get 12v to the pump then would seem either a fault with the two relays, which share a common coil voltage or a faulty control unit not giving out the 'on' voltage, though that might be because its getting a fault signal from elsewhere ..

good luck..

[Esaus]

I've been measuring different cables today to rule out possible faults. Most of them seem ok and i tested one wire at a time. When it comes to the relay coil wires going to the ecu i can't detect a voltage for the relay coil to MR connection. It is a red and black small wire. The 5 pin green relay clicks and a small voltage is applied for a short time over the coil before it stays in the open position, during which a small voltage that goes from the abs warning light goes through the relay and to ground. I guess this is due to that it detects the abs fault so it says open. The black won't click as there doesn't seem to be a voltage going through the coil. Since the error points to the motor relay open circuit this seems to be the problem. If I was better at reding wiring diagrams I would have seen this to start with and checked it first. Oh well.. I ordered two replacement relays yesterday so I'll see if they make a difference.

I guess what is left is to trace the red and black wire to see where it goes. I can't find a red and black wire on the connectors to the abs module. I tried checking continuety. Im not sure the wiring diagram is 100% correct. It might fork off somewhere and change colour or something. I unbolted the abs module but left the brakehoses on it and pulled the harness out a bit. I will continue at a later date to try finding the fault as I will get some parts for the car tomorrow. I also ordered a cheap tone generator that can be connected to the circuit and using a probe you can find the cable. Would make it easier to trace if there is a break and where it goes.

If it is not the cable that is broken it might in the end be the ECU that is at fault and I'll get a new abs module for the car. Found some cheap used replacements on eBay and at a local wrecking yard for 90ish €. It was cheaper on eBay.

Thanks for the input. Hopefully I'll fint the fault sometime soon. I'm not using the car so I'm not in a hurry.

[Esaus]

A small addition! How should i read this diagram to make out what cables goes into which connector? First i read it as the B connector where the red, blue and ground cables go from the relays. There are many more B in that diagram than there are cables to that connector. It is really confusing as I don't know where to look for those cables.

Is it the A and B for the actuator? B 1 to 5 as one connector. And A 1 to 8 for the other? It makes sense. The first connector had 4 cables and the other 8 cables. And checking the chart those color cables seem to look like the ones to the other connector.I thought the abs ecu is attached to the ABS module. The haynes manual states that the ECU is integral with the regulator assembly, and not available seperately. If so, where would those other connectors and cables be? confusing!

[Esaus]

Here is how the abs module looks like.

[oldcodger]

As mentioned I do not know anything about the ABS and my ABS unit is rather different to the one you show, I have just one big connector; yours looks much more modular, assume thats the pump on the bottom and the solenoids on the top.

Have provioded a link to download the 2004 Wiring manual ( big file) which explains how to read the colour codes / connection etc

https://dl.dropboxusercontent.com/u/5285770/2004%20Toyota%20Corolla%20Service%20Manual.zip

The wire colour codes might only go as far as the wiring loom connectors, the wires from the connectors into the abs unit might change as they are probably outsourced parts and they might change suppliers.

If it was me ,with the whole ABS unit electrically disconnected, I would first check out the actual pump motor, looks like the red and black wires are the pos and neg with the blue being the feedback. If so then do a resistance check across red and black to see if there is anything there, or just open circuit or short circuit.

If some resistance, then I would try 12v , via a temporary fuse, across the motor to see if it actually pumps and work back from there.

[Esaus]

Thanks for the link! I'll try to check the pump and connect it to the Battery with a fuse the coming days. I had a check at the wiring diagram. Wish mine was as easy to read and see what connectors it has. Thanks!

[Esaus]

I tried the abs pump today by wiring the 2 wires from the pump directly to the Battery with a fuse inbetween. The abs pump started and ran well when i tested it. I tried tracing the red and black wire from the relay and It goes back the wiring loom towards the Battery and seems to forks off just before the fuse box into the left quarter panel. I looked where i was able to see under the left and right kick panel for any ecy i could see. And checked under the glovebox on the right side. All i saw was a brown ecu, which i think is for the central locking,

So if i read the diagram correctly there should be an ecu inside the dash? Wouldn't the wires go to the abs modulator if the ecu was attached to it.

Why can't it be easier..

[oldcodger]

Can imagine your frustration, but without the exact diagram its going to be a hard job.

In very general terms for any electrical units, the wiring is the last thing likely to be causing the problem, unless you know there is likey to be a chance it might have been disturbed or worked on before ... ?

Sometimes certain press on wiring connectors to ecus etc can loosen or oxydize , but unplugging and replugging usually has a contact cleaning effect.

Exactly where the ABS ECU is on your car I'm not sure, but all mine (2006) seem to be under the dashboard.

The pump running sounds good news, but you do not mention about that third wire running from the pump motor.

I would suspect it should be giving out a voltage to the ecu so perhaps if you measured it with your voltmeter, with no pump running then with the pump running to see if it is send a signal out.

However it might also be a control signal coming from the ECU, so go carefully.

[Esaus]

Well the first priority is to find the ecu without taking apart everything. Then i can see if the red and black wire belonging to relay circut is working. Then i might also see if the return wire MT from the motor has a signal to the ecu as well as everything else. The haynes manual im looking at has the ecu on the abs pump but it looks different on the images (what i can see anyway). It has the face of the module with the ecu attached. Not like mine. The wiring diagram that i have shows the correct wires going to the abs modulator. And since there isnt a big contact it has to be somewhere else.

[oldcodger]

Looking at the diagram you posted it shows the wheel sensors and pump all going into the abs ecu.

If the photo of the abs unit is what you have then I would say the ecu is inside that top metal cover.

If you look at that top wiring connector on the metal plate the colours of the wires look like they match up with the colours of the wheel sensors in the diagram R ,G, W, B, P, B, Y V , well I can see 5 of those colours

Many of the other wiring connectors shown in the diagram are really internal connections inside the abs unit /ecu I would suggest.

The manuals I have, 2002 onwards corolla and my old 1998 onwards Avensis both state the abs ecu is inside the modulator unit.

[Esaus]

Those wires are the colors that go into the abs actuator seen in the A7 B (1 -5) and A6 A (1-8). The wiring loom connects to those 2 connectors and then the cable colors change to those you see in the image from the connectors to the module.

The incoming cables have the colors: Blue red, Blue white, Brown white, Red white, Red green, Green black and Green yellow for A. The B has Blue, red, blue orange, white black. The red black wire going from the motor relay to the abs ecu doesn't connect to any of those 2 connectors that connect directly to the abs module. Therefore i think its elsewhere. Although it may be as you say.. im a bit confused at all this haha. Took a day of it and installed the front disc brakes instead and was going to change sparkplugs and auxilliary belts but it started raining heavily.

I would suggest that the incoming cables from the abs sensors go to the ecu and from there through those cables to the actuator.

[oldcodger]

Right, might be easier then to trace those solid coloured wires from the abs wheel sensors into wherever the abs ecu may be.

Perhaps the rear ones might be easier to trace as theres not as many other wires around them as the front ones.

Rather than just under the dash ,have you looked behind those small panels in the footwells, to the front of the front door pillars.

Also on my later model things like the Air bag control unit is under the centre console near the handbrake.

[Esaus]

I found a workshop manual for a 97 corolla sedan model that has the abs module above the fuse box under the drivers side dashboard. I will take a look there this weekend. Only need to remove the lower panel to gain access i hope. It also had some fault finding diagrams and how to check for errors. It might be worth a try.

I have already checked both drivers side and passenger side kickpanels, They contain relays and some connectors but no ECU components. I have done other repairs to the car this week. Replaced, sparkplugs, brakes all around and a temperature sensor.

[Esaus]

An update on the abs ecu search.

I found the ECU in the location stated in the workshop manual for the sedan. It was behind the fuse box under the drivers side dashboard. I had to remove the lower panel and lay upside down to get access.

I checked the red and black wire going to the relay from the ecu. I had continuety! Making me not happy. I also proceeded to check the wire to the other fuse and it worked aswell. I also checked the pump motor feedback wire and it was ok aswell. Just in case i also checked that the ecu got 12V from the ignition, which it got. So all in all it seems that the ecu itself is faulty. I removed it and have it in my hand now.

The question now is: Will a replacement ecu from the scrapyard need reprogramming? Or is it just plug and play on these older type abs ecus?

The ecu has FFL written on it. ABS toyota 12V japan. And code 89540-12410. On the bottom side it has the code GJ03A written on the case. Is this an id for this particular ecu. The other ecus on the scrapper webpage have different codes in that place.

I can get a replacement ECU from germany through eBay for 50€. Half the price of local scrap yards.

[oldcodger]

Good the hear you have finally found the ecu, well hidden !

Does sound like you have eliminated most things on the wiring side, though one last thing I would check.

On that diagram you can see that resistor by the pump, it goes from the negative connection to the pump and then out via the MT terminal.

If its a resistance you should be able to put you multimeter across those two point as see a resistance of some value.

Only do the reading with the wiring connectors unplugged or the rest of the circuit will affect things.

It could be very low , possibly showing virtually 0.00 or it could be in the high ohms range such a 470k ohms.

If you just get no reading eg open circiut then that might be the problem, the ecu is not getting any feedback ?

Worth a try for 5 mins of checking

As for a replacement ecu needing reprogramming or the various model codes / type - sorry have no idea.

Does there look like any form of burning around any parts it , a pic would be interesting to see.

[Esaus]

I could check the resistance over the Red and MT line tomorrow. I asked some sellers of the ecu online if they require reset. The local scrapyard had a cheap one for 50€ so I'll prob check with them. They arent open on weekends so im not in a hurry.

The module has a metal shield around it. The shield is pressed in place with two studs so i cant check inside without trying to pry those. The shield is a bit rusty on the top. Don't see any burning on anything. It doesn't look like its shielded from moisture. I can see connectors and a circuit board through the slot between the connector and the metal shield.

[oldcodger]

Worth checking that resistor, just in case..

Also now you have found the ecu and disconnected it, have you reconnected it and run the car to see if the fault has cleared ? sometimes just a remake of that connector can clean a oxydizing connector and so the fault ..?

If it seems to be the ecu, then before you order a replacement it might be worth just opening up that box to see what the board is like.

The fold over tabs might be all thats holding the lid on, those two studs might be for connecting earth wires to the lid internally, though if not you will have to drill / file their heads off.

With it being a pre 1997 design it might be more discrete components and possibly some cause of the failure might be evident or even repairable ..?

[Esaus]

I tried running the car after i had the connectors off and reconnected there was no change. The connectors are really clean and shiny. No corrosion at all. Yeah i might check inside. If its broken might as well. I've seen som repair videos of some volvo ecus where they solder a few connectors that often come loose. Might be something as easy as that. The pressed on studs will be easy to press with a good pliers if they are in the way.

Edit:

This whole thread seems to be a long one haha.

I got a reply from the eBay seller of one of the ecus from germany. They said that their ecu is plug and play and don't need reset or reprograming. If the number matches it should work.

I also checked the resistance over the MT and pump motor power and ground and i get a resistance around 33 Ohms and 36 Ohms for the ground connection.

[Esaus]

I have opened the ecu and looked inside. I can't see any broken barts but one of the wires to the connectors is a bit black at the end. However it isnt connected to any wire in the car. This car doesn't have the feature its connected to. I can't see any other broken or charred bits. The board is in good condition. Coated in some kind of sealant over the board. I think one of the chips might have been replaced at some point. The solder on its connectors isn't as clean as the other one. I'll order a replacement ecu and see if it works.

[oldcodger]

Excellent photos, as you say it all looks physically sound.

Looks a very advanced surface mount board for something made 20 years ago; looks like some custom Toyota chips as well , so little chance of getting those components.

Any resistance reading from across that pump resistor ?