BMW X5 Short Circuit
Doing electrical work can be interesting at times, and you never know what you will discover to be the cause of the problem. For example, a customer brought us his 2001 BMW X5 with the 5L40-E automatic transmission in failsafe. Another shop had worked on the engine and told him that the problem was with the transmission. When we checked for codes it had multiple codes in the engine control module (Figure 1).
Double Trouble
Electronic failure can be very similar to a mechanical failure in that when one thing goes wrong, it can cause another part to fail. If you are not careful, you could make a repair that doesn’t fix the original cause of the failure, leading to a repeat failure after repairs.
On-the-Road Diagnosis
The car in Figure 1 is a 2000 BMW 528i that had been to a couple of transmission shops before I got to it. The complaint was that the transmission was in failsafe mode. The car started and moved but would not upshift. The other shops also said they could not communicate with the transmission EGS module.
Even Failsafe Is Subject to Change
Since then, technology has leaped forward at a vicious pace, not breaking for breath. And with this technological race among the “Big 3” manufacturers (U.S., Japan and Europe) comes the need for various computer strategies. Failsafe is one of those strategies that has experienced a change.
Intermittent No Voltage
When a vehicle has been in failsafe or limp mode, it is important to check for codes to see what has caused this condition. If multiple codes are present, check to see whether there is something in common with each one.
