BMW E3. 9 5 Series Transmission Fail Safe 1. CLICK HERE FOR REPAIR PARTS FOR THIS ARTICLECLICK HERE FOR BMW E3. PARTSIn this tech article I will explain what it means when FAIL SAFE is displayed via your instrument cluster. I will also give you some tips on diagnosing transmission faults, mechanical and electrical. The diagnostic steps used in this article to verify a faulty transmission ECU are advanced, however you can learn a lot from the process and help answer your questions when this problem arises for you. Remember when working with electronic control modules, always disconnect the battery before unplugging or plugging one in and do not expose them to static electricity. Safe Handle Has Been Closed Serial Port' title='Safe Handle Has Been Closed Serial Port' />Do you love that sensation of suddenly being hurled forward when you have to abruptly slam on the brakes If youre in a selfdriving car, the effects apparently. RTI specializes in remote control products for AV, lighting, security and more for your home or office. Learn about our custom automation systems today. The automatic transmission in BMW E3. The ability to adapt shift points depending on pressure and slip extends the lifetime of your transmission. What this means for you if you have a FAIL SAFE message indicating the transmission has entered the emergency program is that the trans ECU has been adapting the transmission to maintain a normal feel up to the point where it could no longer adapt and reached a fault limit. Once a fault limit is met, the trans ECU puts the trans in FAIL SAFE or limp mode. When a malfunction occurs within the transmission, FAIL SAFE will prevent unintended gear shifts slipping. The following occurs in FAIL SAFE mode All shift solenoids are de energized via TCM internal relay. The pressure regulation solenoid is de energized resulting in maximum line pressure. The torque converter clutch is de activated. The reverse lockout function is cancelled. Safe Handle Has Been Closed Serial Port' title='Safe Handle Has Been Closed Serial Port' />Shift lock solenoid is de energized. Fault indicators are active FAIL SAFE displayed in instrument clusterThe message location or indicator varies depending upon model, year and cluster type. High version instrument cluster will display a message in the driver information display. Vehicles with low version clusters will display a fault symbol in the cluster. During failsafe mode the transmission will be shifted into a higher gear to allow the vehicle to be driven to a shop. Depending upon application, the transmission will shift into 3rd or 4th gear on a four speed, and 4th or 5th gear on a five speed. For example the A5. Wondershare Dr Fone Ios Crack. S3. 60. R transmission will go into 5th gear when there is a mechanical malfunction and 4th when there is a power failure to the TCM, this is a key note to remember when diagnosing. Since pressure regulation ceases, the shift to failsafe mode will be abrupt or harsh, unless the transmission is already in the failsafe gear. The check engine light will also be illuminated by the DME. Always check the DME and trans ECU for fault codes. See our article on how to read DME fault codes. If you receive a fault code for transmission slip or gear ratio, your problem is likely that the transmission has reached it adaptation limit. Start by checking the fluid level and condition. If your transmission was shifting harsh before the fault, it could be worn out, for example worn clutches or hard seals. Always check that your shift linkage is properly adjusted before condemning your transmission. When diagnosing an issue keep the following in mind Shift quality issues consist of harsh up or down shifts, improper shift points and erratic shifting. These complaints could be related to electronic software issues or hydraulic mechanical problems. As with most concerns, check the transmission fluid level and condition as well. Before digging too deep on delayed upshift issues, make sure you consider when this occurs. It could be normal operation, such as the warm up phase program. Always check front tires for proper inflation pressures, correct size and matching brand and model. Also check for uneven tire wear. Variations in front tire size from left to right can activate the curve recognition feature. The TCM will interpret the difference in wheel speed signals as being a turn and suppress or delay upshifts. Slipping is usually associated with a fault code. Be sure to check the transmission fluid level and condition. Then check the trans ECU and DME for fault codes. Noises and vibrations require a good visual inspection. Look for loose transmission or engine mounts. Check the driveshaft, drive axles, center bearing and driveshaft flex disc. Also check the lateral alignment of the driveshaft. No forward or reverse gear, Start by checking transmission fluid level and note the fluid condition. Inspect for leaks and external transmission damage. When investigation transmission leaks, be sure to verify that the suspected leak is actually transmission fluid. Engine oil, hydraulic and brake fluid can be mistaken for a transmission leak. Check the transmission cooler lines, transmission cooler and transmission pan gasket. Try to locate the source of the leak. Do not make any major repairs until the technical hotline is contacted. Fault Codes Perform a complete vehicle scan on all vehicle systems. It is important to check all systems in the event that a related system is causing the transmission fault. Always record the fault codes and fault conditions. Figure 1. This is the warning message you will see when there is a fault with the automatic transmission. FAIL SAFE means the transmission is in limp mode, in limp mode you only have one gear and no torque converter lock up. If you see this message, pull over and have the vehicle towed to where you can work on it, unless it is a short drive. The BMW E3. 9 I received this message on was stuck in fourth gear. Do you remember from the earlier part of this article what that means That means it is an electronic issue with the ECU BMW describes it as power failure. This means I am likely chasing an electrical issue. So I can skip all my tips from above on dealing with mechanical issues. Large Image Extra Large Image. Figure 2. First thing I did was try to scan the transmission ECU for fault codes. I received no communication. Telling me the module was not responding. I then checked the DME for fault codes and I had a fault for no CAN signal from the trans ECU. This fault code also confirms the trans ECU is offline. The scan tool uses one bus circuit to communicate with the trans ECU, the DME uses another called the CAN bus. Since the trans ECU was not responding on both, this told me it probably wasnt a short in the one of the bus circuits. Large Image Extra Large Image. Figure 3. Next I check the instrument cluster for faults. It also had a message for no communication with the trans ECU. Now I am ready to start testing the electrical circuit. Start by removing the engine covers. Large Image Extra Large Image. Figure 4. Then loosen the four 4mm Allen fasteners for the E box lid and remove it. Large Image Extra Large Image. Figure 5. Next, remove the small Phillips head screw green arrow from the trans ECU electrical connector. Disconnect the battery, wait five minutes after disconnecting. See our tech article on battery replacing and reconnecting. Pull the trans ECU up and out of the E box. Then disconnect electrical connector by opening metal lever and pulling connector off. Then remove connector from black plastic housing. Reconnect the battery. See our tech article on battery replacing and reconnecting. Disable Open New Window Javascript Object. Large Image Extra Large Image. Figure 6. First I check that the trans ECU is getting good battery supply voltage. I load the circuits with an incandescent test light to check for voltage drop and there is none. I do this on all three battery supply voltage pins. On my vehicle, it was Pin 2. Large Image Extra Large Image.