98 LS400 MOT failure - Airbag light

Gorodish · February 15, 2017

Hi all - I'm in a conversation with a nice chap about the potential purchase of a '98 LS400 that's been off road for 3.5 years without an MOT as the Airbag light is on.

Apparently he had it diagnosed as the Airbag ECU.

I can see that this is available as a breakers part for reasonable cash on eBay but I gather it is a complete PITA of a job as the ECU is virtually inaccessible in the transmission tunnel. Has anyone done this job? Is it likely to be the ECU anyway? Or should I just take the dashboard light out and hope for the best (joke - I think!).

Basically weighing up if it is worth the risk - it is a low mileage car and deserves to be saved but not at any cost!

Most of the Airbag advise on the web is for earlier cars.

Tom

wildpolish · February 15, 2017

Hi Tom,

i wont be surprised if it is caused by the ABS ring or wheel speed sensor rusted and not sending right or no signal.

Cheap and simple solutions first

Hope that helps

Gorodish · February 15, 2017

Massive senior moment (and I'm only 51!) - I meant Airbag not ABS! You are quite right re ABS of course! Edited to fix

T

Britprius · February 15, 2017

The best advice I can give is to have the fault code checked for the fault. This should confirm a faulty ECU or a sensor fault on a given wheel. The code should be a generic code meaning most code readers should be capable of reading it. List of Lexus codes below.

C0226 ABS Actuator Solenoid Circuit (Cel.) or ABS Solenoid Valve Circuit (MR) C0236 ABS Actuator Solenoid Circuit (MR, Cel.) C0237 Speed Sensor Circuit (Cel.) C0238 Speed Sensor Circuit (Cel.) C0239 Speed Sensor Circuit (Cel.) C0246 ABS Actuator Solenoid Circuit (MR, Cel.) C0256 ABS Actuator Solenoid Circuit (MR, Cel.) C0273 ABS Motor Relay Circuit (MR, Cel.) C0274 ABS Motor Relay Circuit (MR, Cel.) C0278 ABS Motor Relay Circuit (MR, Cel.) C0279 ABS Motor Relay Circuit (MR, Cel.)

John

Britprius · February 15, 2017

18 minutes ago, Gorodish said:

Massive senior moment (and I'm only 51!) - I meant Airbag not ABS! You are quite right re ABS of course! Edited to fix

T

Ok I'LL have another go. List of airbag codes:-

B0100 Short In D Squib Circuit / 13 B0101 Open in Driver-Side Air Bag Module Squib Circuit /14 B01023 Short in D Squib Circuit (to Ground) / 11 B0103 Short in D Squib Circuit (to B+) / 12 B0105 Short in P Side Air Bag Squib Circuit / 53 B0106 Open In P Side Air Bag Squib Circuit / 54 B0107 Short In P Side Air Bag Squib Circuit (to Ground) / 51 B0108 Short In P Side Air Bag Squib Circuit (to B+) / 52 B0110 Short In Side Squib (RH) Circuit / 43 B0111 Open In Side Squib (RH) Circuit / 44 B0111 Cab Side Airbag Circuit (Range/Performance) Malfunction ( 4 AV.’99) B0112 Short In Side Air Bag Module Squib (RH) Circuit (to Ground) / 41 B0113 Short In Side Squib (RH) Circuit (to B+) / 42 B0115 Short in Side Air Bag Module Squib (LH) Circuit / 47 B0116 Open In Side Air Bag Module Squib (LH) Circuit / 48 B0117 Short In Side Squib (LH) Circuit (to Ground) / 45 B0118 Short In Side Air Bag Module Squib (LH) Circuit (to B+) / 46 B0121 Seat Belt Buckle Swith, RH malfunction / 26 B0122 Seat Belt Buckle Swith, RH malfunction / 26 B0126 Seat Belt Buckle Swith, LH malfunction / 27 B0127 Seat Belt Buckle Swith, LH malfunction / 27 B0130 Short in P-Side Seat Belt Pretensioner Squib (RH) Circuit / 63 B0131 Open in P-Side Seat Belt Pretensioner Squib (RH) Circuit / 64 B0132 Short in P-Side Seat Belt Pretensioner Squib (RH) Circuit (to Ground) / 61 B0133 Short in P-Side Seat Belt Pretensioner Squib (RH) Circuit (to B+) / 62 B0135 Short in D-Side Seat Belt Pretensioner Squib (LH) Circuit / 73 B0136 Open in D-Side Seat Belt Pretensioner Squib (LH) Circuit / 74 B0137 Short in D-Side Seat Belt Pretensioner Squib (LH) Circuit (to Ground) / 71 B0138 Short in D-Side Seat Belt Pretensioner Squib (LH) Circuit (to B+) / 72 B1100 Airbag Sensor Assembly Malfunction (Progr. Avens) / 31 соотвт B1135 SRS Control Module – poor multi-plug connection / 24 B1140 Side Airbag Sensor Assembly (RH) Malfunction / 32 B1141 Side Airbag Sensor Assembly (LH) Malfunction / 33 B1142 Door Side Airbag Sensor (RH) Malfunction B1143 Door Side Airbag Sensor (RH) Malfunction B1144 Door Side Airbag Sensor (LH) Malfunction B1145 Door Side Airbag Sensor (LH) Malfunction B1146 Side Crach Sensor, RH B post Malfunction / 32 B1147 Side Crach Sensor, LH B post Malfunction / 33 B1148 Front Crach Sensor, RH Malfunction / 36 B1149 Front Crach Sensor, LH Malfunction / 37 B1153 Seat Position Sensor malfunction / 25 B1154 Side Crach Sensor, Rear RH in C posts / 38 B1155 Side Crach Sensor, Rear LH in C posts / 39 B1156 Front Airbag (Front crach) Sensor (RH) Malfunction / 15 B1157 Front Airbag (Front crach) Sensor (RH) Malfunction / 15 B1158 Front Airbag (Front crach) Sensor (LH) Malfunction / 16 B1159 Front Airbag Sensor (LH) Malfunction / 16 B1160 Inflatable curtain RH short circuit / 83 B1161 Inflatable curtain RH open circuit / 84 B1162 Inflatable curtain RH short circuit to Earth / 81 B1163 Inflatable curtain RH short circuit to Positive / 82 B1165 Inflatable curtain LH short circuit / 87 B1166 Inflatable curtain LH open circuit / 88 B1167 Inflatable curtain LH short circuit to Earth / 85 B1168 Inflatable curtain LH short circuit to Positive / 86 B1180 Driver’s Air Bag, Stage 2 – short circuit / 17 B1181 Driver’s Air Bag, Stage 2 – open circuit / 18 B1182 Driver’s Air Bag, Stage 2 – – short circuit to Earth / 19 B1183 Driver’s Air Bag, Stage 2 – short circuit tp Positive / 22 3 e.g. on a ‘00 Toyota Celica GT-S, Avensis D-4D ‘03 4 I read on this Vehicles DTC on Toyota / Lexus from al tech page (www.alflash.narod(blocked word)/) Note: Not all trouble codes are used on all models 4 B1185 Passenger Air Bag Stage 2 short circuit / 57 B1186 Passenger Air Bag Stage 2 open circuit / 58 B1187 Passenger Air Bag Stage 2 short circuit to Earth / 55 B1188 Passenger Air Bag Stage 2 short circuit to

Sorry there is a lot of them.

John

Gorodish · February 15, 2017

John - most helpful - will see if I can take an OBD reader tomorrow when I have a look

T

alien1974 · February 15, 2017

mk 4s aren't obd11 compatable mind

Tinonline · February 15, 2017

I think it's a decent motor and you want it...then it's a great bargaining point as replacing these items correctly is not cheap etc etc..

Requisite huffing and puffing and a reluctant purchase you go home with said car smiling.

Of course check for cambelt change etc.

You can do pita route or other!

Just remember - only one Lexus per household...they are in very short supply.

Gorodish · February 17, 2017

Has anyone done a DIY Airbag ECU change on a Mk4? Is it under the ashtray above the transmission? Is there a guide anywhere?

The car looks absolutely lovely in photos but not been through an MOT since 2013!

ambermarine · February 17, 2017

Gorodish

Bite the bullet and buy it,The airbag light is a repairable problem and at the end of the day if the rest of the car is sound you will be getting a rare example of the best Mark that the Lexus LS400 came as.

Get a AA survey and use the result to convince the present owner he as to accommodate your offer,he his not likely to sell it if it cannot pass a MOT.

With regard to DIY fix on the airbag unless you have extensive knowledge of the technology I would not recommend it,they are dangerous things if not handled properly .

Find an independent who is clued up on airbags and get it repaired properly.

steve2006 · February 17, 2017

If you pull back the carpet on the front passenger side transmission tunnel you will be able to see the SRS ECU which will have yellow coloured plugs, the problem is it is mounted below the ashtray and is surrounded by a tubular steel framework making removal difficult.

A common cause of the warning light illuminating is a dodgy connector under the driver's seat so check under there (yellow plugs again) or the clock spring under the steering wheel.

Getting the fault codes confirmed is a must before diving in and if this does point to the ECU I would obtain a replacement ECU then remove the plugs from the one already fitted ( disconnect the car Battery negative and leave at least 30 minutes to ensure back up system is discharged for safety before touching the airbag ECU) then plug in the replacement just letting it hang down and see if the light goes out now. If it does then go ahead and fit it properly if it doesn't then you have saved removing a good ECU and the fault lies elsewhere.

Mikaelse · March 26, 2017

My 1995 LS400 Airbag light came on intermittently after start and more and more often.
It was the 5 revolutions cable thing behind the steering wheel transfering cabling to the steering wheel that was broken.

Bought a new OEM from Amayama.com in Japan. Fixed the problem.

steve2006 · March 26, 2017

No updates on this, would be good to know the outcome?

Gorodish · March 26, 2017

For a number of paperwork related issues i wasn't able to complete the purchase yet, but hopefully will be picking the car up in early April. Will let you know how i get on. Thanks to everyone for your help.

Gorodish · April 27, 2017

Well, the car is now MOT'd and running fine. It is so nice to be driving a LS400 again!

Slight issue - the garage passed the car with the Airbag light still lit. I didn't ask them to do this - was quite surprised. They'd thought that changing the alternator might make the difference. Anyhow at least I can sort this out at my relative leisure now!

Steve - thanks so much for the clear instructions on finding the Airbag ECU. I'm just going to have to be brave and start pulling stuff apart - I don't suppose if anyone knows if there is a photo or video explanation for changing the Airbag ECU on a Mk4?

The car is otherwise a dream. Perfect colour, perfect interior, 78k and FLSH. Just needed 4 tyres and an alternator after 4 years off the road. What cars these are!