Your 2002 BMW 745Li won’t start—and whether it cranks or not, it’s frustrating. This model (part of the E65/E66 generation) is known for its advanced electronics, but that also means more potential failure points. The good news is most no-start issues on this 7 Series can be traced to a handful of common causes.
In this guide, we’ll break down why your 745Li won’t start, how to figure out the root cause, and what steps to take to fix it.
Understanding the Two Types of No-Start Situations
Before diving into fixes, it’s key to identify which type of no-start issue you’re facing:
- Cranks but won’t start: Engine turns over but doesn’t run.
- Doesn’t crank at all: No engine sound—just a click, or total silence when pressing the start button.
Each scenario has its own set of causes. We’ll cover both below.
If Your 2002 BMW 745Li Cranks But Won’t Start
1. Failing Fuel Pump
The 745Li is prone to fuel pump issues, especially if the pump is original. If the engine isn’t getting fuel, it won’t start even if it cranks strongly.
Signs:
- No fuel pump sound from rear seat when pressing start
- No fuel pressure at the rail
- Check engine light may or may not be on
Fix: Check fuse #59 and relay for the fuel pump. If those are fine, the pump may need replacing. Learn more about BMW fuel system issues here.
2. Crankshaft Position Sensor Failure
If the crankshaft sensor fails, the ECU won’t know when to trigger ignition and fuel injection.
Signs:
- Cranks endlessly with no spark or injector pulse
- No RPM movement on dash while cranking
Fix: Replace the crankshaft position sensor with a high-quality OEM part. It’s a common issue on this V8 engine.
3. Immobilizer or Key Recognition Problem
The EWS system (BMW’s security module) may block starting if it doesn’t recognize your key fob. This can also happen if the car’s battery recently died or was replaced.
Signs:
- Cranks but doesn’t start
- Yellow or red key symbol on the dash
- “Key not recognized” message on iDrive
Fix: Try another key. If that fails, the EWS-DME sync may need to be reset by a BMW specialist. Click here for more on BMW’s immobilizer systems.
4. Ignition Coil or Spark Failure
If the fuel system is working but there’s no spark, ignition system faults may be the issue.
Signs:
- Strong fuel smell from exhaust after multiple cranks
- No combustion or starting
Fix: Test for spark at the plugs. If there’s no spark on all cylinders, check fuses and the DME relay. If only one or two coils are dead, replace those coils.
If Your 2002 BMW 745Li Doesn’t Crank At All
1. Dead or Weak Battery
The 745Li is notorious for draining its battery due to power-hungry electronics, even when off.
Signs:
- iDrive powers up slowly or shuts off randomly
- Clicking when pressing the start button
- No cranking sound at all
Fix: Test battery voltage (must be 12.4V+). If it’s low, jump-start the car or replace the battery. Also check the IBS sensor (Intelligent Battery Sensor) on the negative terminal, which can block startup.
2. Starter Motor or Relay Failure
The starter may fail after years of use, especially in higher-mileage vehicles.
Signs:
- Single click or total silence
- All lights and electronics work fine
Fix: Check the starter relay. If bypassing the relay gets the starter going, replace it. If not, the starter motor itself may need replacement.
3. Ignition Switch or Start Button Issues
On the 745Li, the start button and ignition system rely on multiple modules working together. A failed switch or CAS (Car Access System) module can stop everything.
Signs:
- No crank or engine noise at all
- Instrument cluster lights up but nothing happens
Fix: Perform a full scan with BMW-specific software. If CAS or IBS faults are logged, they’ll need repair or reprogramming.
4. Gear Selector Not in Park or Neutral
If the transmission selector isn’t registering “Park” or “Neutral,” the car won’t allow a start for safety reasons.
Signs:
- Message on iDrive saying “move to Park”
- Can’t move gear shifter out of place
Fix: Reset the gear selector or check the transmission range sensor. Also ensure the brake pedal switch is working.
How to Diagnose the Problem
Here’s a step-by-step process to narrow down what’s going wrong:
- Check battery voltage: Use a multimeter or jump pack.
- Listen for fuel pump prime: Should hum briefly when ignition is on.
- Scan for fault codes: Use a BMW-specific tool like INPA or ISTA.
- Try a different key: Rules out key recognition failure.
- Check for spark and fuel: Spray starting fluid to test fuel delivery.
Read more on BMW-specific diagnostic methods here.
Less Common Causes
- Blown engine fuse (check both glove box and trunk fuse boxes)
- Corroded battery cables (check for looseness or acid damage)
- Water damage in DME or trunk modules (especially after heavy rain)
When to Get Help
If you’ve gone through the checklist and the car still won’t start, it’s time to call in a BMW specialist. The 745Li has complex electronic systems, and misdiagnosing a no-start can lead to unnecessary part replacements.
A BMW scan tool can read live module data and show exactly which system is blocking the start process—fuel, ignition, key sync, or security.
Conclusion
A 2002 BMW 745Li that won’t start can be frustrating, but it usually comes down to the basics—battery, starter, fuel, or key recognition. Start simple and work methodically. You don’t need to guess; these cars are smart enough to tell you what’s wrong if you have the right tools.
Want to learn more about BMW repair tips and high-tech troubleshooting? Click here to explore more detailed BMW tech guides and stay ahead of costly breakdowns.
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