When the Engine Control Unit (ECU) on a BMW, Mini, Range Rover determines a problem such as low transmission fluid, low voltage, bad alternator, torque converter slipping, etc., with the potential of causing damage to the gearbox, it forces the transmission to enter TRANS FAILSAFE PROG. In failsafe mode, the transmission stays in one gear, and engine output is reduced to avoid further damage to the transmission.
If your BMW, Mini, or Range Rover displays a TRANS FAILSAFE PROG error message on the instrument cluster, pull over, turn off the ignition, wait a minute, and restart the engine. Don't panic thinking you need a new transmission without first checking the charging system (alternator and battery). Auto parts stores such as AutoZone and Advance Auto Parts can perform a free charging system test.
The most common problems that trigger BMW TRANS FAILSAFE PROG warning messages are:
- bad battery,
- faulty alternator,
- low transmission fluid level.
If the vehicle voltage doesn't stay constant, the engine control module will trigger the TRANS FAILSAFE PROG.
If your BMW battery is weak or not holding a charge, follow this guide to learn how to replace a BMW battery.
If the BMW TRANS FAILSAFE PROG error message resets after a restart, it is strongly recommended to have the vehicle diagnosed by a BMW mechanic because, in most cases, the error message returns after a few days.
What does BMW's "TRANS FAILSAFE PROG" mean?
TRANS FAILSAFE PROG is a default setting for a BMW auto transmission when the Engine Control Unit (ECU) detects a transmission problem. It could be a serious problem or something as simple as a discharged battery.
TRANS FAILSAFE PROG is a BMW function that only affects vehicles with automatic transmission. It may also be references to as failsafe mode, fault mode, default mode, and limp mode.
Failsafe mode is designed to protect the transmission. When the ECU determines a glitch or problem that can cause transmission damage, it forces the transmission to stay in one gear, typically 3rd or 4th (not shift), to allow you to drive home or an auto repair shop.
When a BMW is in TRANS FAILSAFE PROG mode, it is only meant to be driven to the nearest auto repair shop. Vehicle speed usually is limited to 40 mph, and transmission no longer shifts properly.
When the TRANS FAILSAFE PROG error message comes up, most BMW owners notice one or two symptoms from this list.
- Transmission stuck in gear
- Check engine light comes on
- ABS light comes on (not always)
- BMW won't accelerate
- Speedometer stops working
- Battery light on
- DSC light comes on
- Tiptronic / manual shifting doesn't work
- The engine has no power
- The service engine is "on."
- Failsafe shows after the engine warm-up
- ATC light comes on
- Transmission stuck in limp mode
- Car won't move or bumps hard into gear
- Transmission won't shift in manual mode
- Trans won't shift into Reverse gear
The following problems can cause the TRANS FAILSAFE PROG message on a BMW.
Weak Car Battery
A low battery voltage is one of the most common problems that cause TRANS FAILSAFE PROG on a BMW. If you are getting the TRANS FAILSAFE PROG after your battery died, there is a high chance the problem is due to low voltage.
First, replace or fully charge the battery. If the battery is over three years olds, perform battery testing to ensure the battery is holding a charge. On average, a BMW battery lasts 3 to 5 years.
Next, read the fault codes in the transmission control module (EGS) and clear any codes that are related to low battery voltage or battery charge very low.
A fully charged battery should read at least 12.6 volts with the engine off. Once the engine starts and the alternator starts to charge, you should get (13.8-14.5 VDC).
- If your battery is reading 12.0 VDC with the engine off, it means the battery is only 50% charged.
- If your battery is reading under 12.7 volts or under with the engine running, you have a faulty alternator.
The first thing you should do when you get a TRANS FAILSAFE PROG error message on a BMW is to test your battery and charging system. Many auto parts stores perform charging system test free of charge.
A bad alternator can cause a BMW to display a failsafe error message on the dashboard. The first sign of an alternator problem is that the battery light comes on, soon followed by a failsafe error message.
If the alternator is bad, it will not charge the battery. After a few minutes of driving, the battery voltage drops below 12.5 volts, which then triggers low voltage fault codes on the engine and transmission modules.
To replace the alternator, a BMW dealership costs between $1200 to $1700, depending on the model. If you decide to replace the alternator yourself, you will be spending between $150 and $300 for a replacement alternator.
Visit your local auto parts store to perform a free alternator test.
Low Transmission Fluid Level
Another common problem that triggers TRANS FAILSAFE warning on a BMW is the low transmission fluid level.
If your BMW displays TRANS FAILSAFE PROG message after it warms up or if you accelerate hard (while pressing the pedal to the metal) and RPMs go up, but the car slowly moves, the problem could be low transmission fluid level.
If the transmission level is low, you will notice that the TRANS FAILSAFE PROG comes up under hard acceleration or when you go through a corner and accelerate at the same time. Under these conditions, the transmission fluid level drops too low that the oil pump can no longer pick up any fluid. The ECU limits the output and puts the transmission in limp mode to avoid damage to the transmission.
Check your transmission fluid level. If the level is low, bring the level to the recommended range.
Next, inspect the transmission oil pan for leaks. BMWs are known to leak transmission fluid from the transmission oil pan gasket. If that's the case, replace the gasket as soon as possible.
The ABS module (also known as DSC) on a BMW can fail and trigger several warning lights, including ABS, DSC, along with the TRANS FAILSAFE PROG to come on.
The transmission control module (EGS) and anti-lock brake model (ABS / DSC) communicate with each other, and if one has a fault, it will affect the operation of the other unit.
The cost of replacing an ABS module at a BMW dealership can range from $1700 to $2500. A more affordable solution is to remove your old ABS module and send it for repair to a facility specializing in ABS module rebuilding.
Many ABS repair companies list BMW ABS repair services on eBay.
Other possible problems
- Engine Control Module (DME) - A faulty DME can set BMW transmission failsafe mode. In some cases, the problem may start with a bad thermostat which can leak and cause electrical shorts for the MAF and DME if DME is bad and needs to be removed, cleaned, replaced, and reprogrammed.
- Dirty transmission filter or fluid - BMW may state that you do not have to change the transmission fluid. Many BMW mechanics and automatic transmission shops, on the other hand, recommend that you should change the BMW transmission fluid every 60,000 miles. Changing the fluid on high mileage, BMW is not recommended as it can result in flares and slipping because the old fluid is thick, helping the worn clutch packs stick better.
- Brake light switch - A faulty brake light switch can cause the TRANS FAILSAFE PROG error to come up. The brake light switch is mounted above the brake pedal and is very easy to replace.
- Valve Body - The transmission valve body may be faulty and needs to be rebuilt or replaced. BMW transmissions are typically made by ZF GETRIEBE GMBH. Certain ZF transmissions have a design flaw involving the o-rings and clearances.
- MAF Sensor - A faulty mass airflow sensor can cause a BMW to enter failsafe mode. If you have any current or stored fault codes related to the MAF sensor, fix those first.
- Serpentine drive belt - A faulty drive belt may cause slippage for the alternator pulley, leading to low charging voltage. If you notice that the power steering gets hard, or the error code comes up when the vehicle is parked, idle, or at a stop sign, check or replace the serpentine belt and tensioner if needed.
- Voltage regulator - The voltage regulator may be the reason why your transmission is going in limp/failsafe mode. The problem is not always the lack of being able to charge the battery. In some cases, the problem is due to overcharging. Check the vehicle operating voltage. If it is over 15 volts, the regulator may be the culprit. The voltage regulator is mounted at the back of the alternator and usually is replaced along with the alternator even though you can replace just the regulator.
- Shifter linkage - On older BMWs, the shifter link connected to the transmission may need to be adjusted. Over time the shifter may get loose or slightly bend so that it doesn't fully engage when placed in DRIVE. This doesn't apply to newer BMW as they utilize drive-by-wire technology. Also, if you select the reverse bear but the transmission is still neutral, the problem could be the link from the shifter to the transmission.
- Electrical issues - Electrical issues can cause network communication issues which can lead to the transmission module not being able to community with the engine control module. Even using the wrong bulb for the brake lights can cause shorts and fault codes in DSC, leading to failsafe errors.
- Loose battery terminal - Check the battery terminals. Clean them and make sure the 10mm nuts are on tight.
- Transmission wire harness - Can get damaged or corroded and prevent communication between valve body and transmission control unit. Unplug the transmission connector and check for water intrusion into the connector.
- Torque converter - When the torque converter starts malfunctioning, you may feel shuddering and even slipping in the drive.
- Ignition Switch - Faulty ignition switch can also cause trans failsafe prog error even though this problem is infrequent and unlikely.
- Transmission range switch - Can get wet when it rains and you drive through water puddles. The dash cluster may not display the correct P, N, R, D indication. Try removing the switch and cleaning, if possible. Also called Gearbox Position or Neutral Switch. If you read codes with INPA, you may get fault codes such as 60 Getriebeschalter ( Gear Switch ); the problem can be the gearbox position switch.
- Blown fuse - Check your fuses. BMWs have two or more fuse blocks, one in the glove box and one in the right rear behind a removable panel or engine bay.
- Crankshaft position sensor - If your BMW has a rough idle, engine stalls, or dies in idle, the problem can be due to a faulty crankshaft position sensor or a faulty MAF sensor.
- Parasitic current drain - A parasitic drain can bring the battery voltage under 11 volts, which causes the failsafe error message to show up as soon as you start the vehicle. It can take some time for the alternator to fully charge the battery and bring the voltage above 13 volts with the engine running.
- MAF Sensor - The mass airflow sensor can cause the engine to go into limp mode, leading to the transmission stuck in gear. BMWs are very sensitive to the MAF sensor. There have been many cases when an aftermarket MAF sensor caused similar symptoms to a bad MAF. It is recommended to use an OEM MAF sensor.
Can I reset the TRANS FAILSAFE PROG message?
In most cases, you can reset BMW TRANS FAILSAFE PROG simply by turning off the engine, waiting a minute, and turning it back on.
If that doesn't work, you can use a BMW scanner to read and clear codes from the EGS module.
We don't recommend ignoring this fault as it can cause damage to the vehicle in the long run. Follow the steps below to troubleshoot a BMW that shows the TRANS FAILSAFE PROG error message.
Can I use any scanner to diagnose TRANS FAILSAFE PROG?
No. A generic code reader like those used at an auto parts store will not read transmission faults. You need a scanner that can read fault codes from a BMW transmission known as the EGS module. Here is a list of scanners that can read BMW transmission codes and reset them.
If your BMW has gone into TRANS FAILSAFE MODE, you should get the vehicle diagnosed as soon as possible.
Even if the transmission resets after you restart the engine, it doesn't mean the problem has been resolved. In most cases, the failsafe mode will return because the issue causing the transmission to enter limp home mode hasn't been fixed.
Start by checking the battery and alternator. Next, check the transmission fluid level. If the battery is working properly and the fluid level is correct, read the fault codes from the transmission control module using a BMW scanner.
Follow these steps to scan your BMW and determine what code is stored in the transmission control unit (EGS). The codes in that module should point in the direction you will have to go.
Possible fault codes that may be stored in the engine (DME), transmission (EGS), and Anti-lock Brake System (DSC):
- P0720 - Output Speed Sensor Circuit Malfunction.
- P0715 - Engine Control Module (ECM) or Transmission Control Module (TCM) detects an irregular signal coming from the input/turbine speed sensor in the transmission
- P0743 - Torque Converter Clutch (TCC) Solenoid Circuit Electrical. This means the engine control module sees a fault in the TCC, which is contained inside the transmission.
- 5F1D DSC Engine management interface.
- 5F42 DSC transmission control limp-home operation
- P0560 - The powertrain control module has detected an abnormal voltage reading. This reading comes from the battery, starting, or charging systems and is deemed abnormal by the DME for being higher or lower than expected.
- 4E87 - Solenoid Valve 4 (shift lock)
- 51AE - CAN brake light signal
- 5088 - Sensor gearbox selector switch
For more help, follow the guide on troubleshooting BMW transmission problems.