BigZed

Just been out again to the car to do a full fault code scan. With ignition on airbag light is off. full scan returned just the 93C2 code as not present but stored. Cleared the code from memory. Cycled the ignition off / on. No airbag light. full scan returned no codes. Applied load to seat, airbag light came on. Cycled the ignition off / on. No airbag light. full scan returned no codes. Back to the original scenario. Still dont know where to go from here. 🤔 Dave, I agree, pressure mat is expensive, and PITA to do. It appears the mat is registering the load, but it doesnt know what to do with the signal. Are the mat and sensor,2 different components ?

I checked the switch position, airbag on. Toggled the switch between on,off and on. After disabled, airbag light came on, when in seat.Turned off ignition, no-one in seat, airbag light on. Airbag enabled light now on without seat occupied. Fault code 93C2, unable to clear code. Scenario differs now, because previously The airbag light only came on when there was someone sitting in the seat. Will now try plugging the emulator back in to see if this allows me to clear the persistant fault code.

Are you suggesting its the sensor and not the mat. are they different components? The bypass mat emulator is plugged in, in place of the the mat plug, so that the mat is not connected to the wiring circuit. So I would have thought that in this condition the emulator is not functioning as expected, and is not completing the citcuit correctly. As I am unable to clear the fault code. As I mentioned in the OP, I still dont understand why once the airbag warning has been triggered, that light goes out after the passenger has exited and the ignition has been cycled off and on. On other vehicles with airbag faults, I have experienced once triggrered the airbag light stays on even after cycling the ignition, until the fault is rectified and the code cleared. I dont believe the passenger airbag has been disabled by the key. However I dont know if the passenger seat components have been disabled through INSTA in the ECU.

2011 116d E87, N47 The issue I am experiencing is the airbag light is off when driver only is belted in the car. When a passenger sits and / or is belted in the car the airbag light comes on with the seat belt sign. When the passenger exits the car and the ignition is turned off and back on again the airbag light is off. The airbag light only comes on when the passenger sits in the car. No codes are stored when the airbag light is off. the fault code 93C2 - SBE seat mat is stored when the airbag light is on. I have tried installing BMW E87 Seat Occupancy Sensor Bypass Mat Emulator Simulator, however all this does when plugged in ses off the airbag light when the ignition is on, and no one is in the passenger seat. I am unable to erase the fault code when this item is plugged in. Uninstalling it, and reconnecting the original wiring, allows me to clear the code, and ab back to the same scenario. I thought that once the airbag fault is triggered, thw warning light stays on until the fault code is erased. What I experience is that the warning is only present when a passenger is in the front seat. Any ideas on how to resolve this.

Hi Dave, Heres an update on this. I employed the services of an auto electrician, who pointed me in the direction of a failed / failing ecu. However he did recommend changing out the MAF sensor first before embarking on the ecu issue, as cloning a second hand unit would be north of £200. It appears from the date code on the Bosch MAF sensor that this has already been replaced within the last 3 yrs, and swapping this out for a new one did not improve the situation, in the terrible running of the car, so I put the old one back in. I bought an ECU and CAS unit and keys ( £40 off ebay) and was going to try this first. I removed my ECU to get the part # from it and left it out of the vehicle until the replacement arrived. 3 days later I had to plug it back in to move the car in preparation for the change out, and to my surprise. It fired up and after a cough and a splutter the motor ran smoothly and was responsive on the throttle, with no smoke, or hesitation. I have tentatively taken it out multiple times on increasing distances and have now covered over 50 miles without any hesitation or smoking. Still have these 2 fault these present and stored, so still requires further investigation, but at least its driveable.. 40E9: exhaust gas recirculation control, position control 4B81: Exhaust gas recirculation rate control, control deviation

Its interesting to note that the ECU (A2249) pin 31 comes from Voltage supply Position sensor, EGR valve So mybe I should be relooking at the EGR valve and wiring harness and connections.

Hi Dave, Heres what I found when testing the MAP and MAF sensors. MAP sensor Found constant voltage wire, and ground wire on the 3 wire plug from harness with mutimeter with ignition on. Back probed the plug on the signal and ground wire at got approx. 1v with engine running. No increase in voltage with increase of revs which was difficult due to the stuttering of engine with exhaust smoke in engine bay. MAF sensor Found constant voltage on red wire (pin 1) on the 4 wire plug from harness with mutimeter with ignition on. Could not find a ground in the plug. The remaining 3 wires were all live with 3.5v on brown (pin 2), 5v on both grey (pin 3) and yellow/black (pin 4) wires. With the ignition off No ground in harness plug on pin 2. No point in back probing as no ground. The issue with the MAF sensor harness wiring is worrying, I guess this maybe an ECU ( expensive ) issue. Any ideas on how to proceed. Thanks. Paul.

Hi Dave, I have used a different diagnostics tool ( Bimmer tool) interesting to note that the fault code 3FF0 is shown, and the description of 40E9 states exhaust gas return controller. ( The bimmerlink tool has the same codes as before} Also the live data is showing a huge difference between the actual and expected air mass reading. Is there anything here which may narrow down the search for a solution? BTW - You mention checking the MAP sensor, is this different from the MAF sensor, and if so do you know where is it located? Thanks, Paul.

FYI, The dpf sensor hose I replaced was #4, and there appears to be 2 exhaust sensors #3 and #5. #5 appears to be for exhaust back pressure.

Hi Dave, Thanks for your reply. If there was an issue with the DPF sensor, wouldnt that have an error code?, I did think it strange that the broken dpf sensor hose didnt show a fault code. How do you suggest I test the dpf and maf sensors? Paul.

OK, so I managed to insall the new dpf pressure sensor hose, which I thought would be a 10 minute job, but turned into a 2 1/2 hour fight. The hose clip on the dpf is a b*tch to get to, to undo and tighten.☹️ I also changed the brake servo vaccuum sensor, took about 20 minutes, with a thin long shafted flat blade screwdriver and a medium length pry bar. Auto start /stop fault warning on dash and fault code eliminated. 😁 Now an update on the symptoms. Ignition on, Engine off. 4A4E glow plug cylinder 3,control 4A6E glow plug cylinder 1,control Ignition on, Engine running 4A4E: glow plug cylinder 3,control 4A6E: glow plug cylinder 1,control 40E9: exhaust gas recirculation control, position control 4B81: Exhaust gas recirculation rate control, control deviation Test runs - No load, vehicle static. Starts on the button first time (hot or cold) idles smoothly (hot or cold) , short or long running times. freely revs, short or continuous pedal depressions. Test runs - Engine under load, pulling away or moving. 1st test run. single stutter on pulling away, and a 8 mile drive without issues, even though the same error codes were recorded at end of journey. 2nd test run Pulling away - engine starts to stutter and losses power, blue / grey smoke from exhaust and engine bay. Moving complete loss of power, stuttering, no throttle response, blue / grey smoke from exhaust , smoke clears when off throttle. No EML on dash, and same error codes. So it would appear that the symptoms have worsened and the drivability of the car is now non existant. BTW - I am using Bimmerlink as the diagnostics tool. Where do I go from here, Back to the EGR valve and cooler ?

Hi Dave, Finally got a chance to clean the EGR valve and MAF sensor over the bank holiday, and cleared all the codes related to them. However the cars symptoms are still the same. but non of the above codes re-appeared. Whilst doing the removal of the EGR valve I noticed that the DPF pressure sensor hose was sheared at the DPF , and the hose was still connected at the other end to the sensor, however this end of the hose looks like reinforeced garden hose, and I believe is someones previous attempt at a fix. The small amount of hose attached the the dpf is different to this a appears to look like original hose. I am now in possession of BMW original spec part # 13628591459 hose and will be working on replacing the broken hose this week. The fault codes I am left with are #1 & #3 glow plugs, which I dont believe are the issue related to the hesitation ( as I dont think its cold enough at the moment) and the brake servo sensor fault which is giving a warning on the dash for the start / stop fault. I have the replacement brake servo sensor which I will be replacing after I have done the dpf pressure sensor hose. Fingers crossed one or both of these are causing the hesitation. I will be doing the glow plugs as well after this, as we will be heading into winter soon. to clear all fault codes and eliminate these from the quation. As always, any tips or suggestions as to the cause of these symptoms, are always welcome. Paul.

Morning Dave, Thanks for your reply. My engine has the electronic EGR valve, is there any tips on how to clean and check this properly. You mention hoses, I believe there are only 2 hoses on this egr for the egr cooler, are you refering to these getting clogged?, I am not aware of any other hoses on the EGR circuit, they are all solid metal pipework. Will inspect the air intake manifold aswell. Exhaust sensor?, Are you refering to the Lambda Sensor. I did noyt get an error code on this. Was the black cloud all the dislodged soot from the clean, and was this an one off. Paul.

Hi, I am new to the forum and have just aquired this E87, as a stop gap motor. Symptoms. From cold start. Motor starts easily and will tick over smoothly. Pull away in first with throttle 1/8 depressed, then into second at say 1500-2000rpm, same throttle and gear change to third. Engine stutters at limited throttle opening, but sometimes clears itself with a little more throttle. These symptons continue for first 20-30 seconds and then the engine is smooth for the rest of the journey. From warm start Intermittently (1 in 10) same symtoms as cold start. I have run a diagnostics scan and have 4x EGR faults, and 2xMAF ( see below) 40E9: 40E9 exhaust gas recirculation control, position control 4B81: 4B81 Exhaust gas recirculation rate control, control deviation 4B82: 4B82 Exhaust gas recirculation rate control, control deviation 4933: 4933 air system, air to EGR mass flow plausibility 3FF0: 3FF0 air mass meter 3FF1: 3FF1 air mass meter Iam guessing that either the EGR and MAF sensor or both need cleaning / replacing. I am thinking to work on the EGR fault first, as this may be triggering the MAF fault. Am I going about this in the righr way, or does anyone have any comments or suggestions as to the cause of the symptoms and error codes, and any remedies or aditional fault finding tips.