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Engine Control Module (ECM)
This photo shows the same type of part you'll receive. Since each used part has its own wear and scratches, yours may look slightly different. Check the product notes for details about the condition of this specific part.

2003 - 2005 BMW Z4 Engine Control Module (ECM) (OEM)

Only 2 left in stock
$87.95

⚠️ ELECTRONIC MODULE NOTICE

This module may require programming to your vehicle by a dealer or qualified technician with professional diagnostic equipment.

  • Ships in a sealed inspection bag for visual inspection
  • Returns not accepted if inspection bag has been opened
  • "Needs programming" is not grounds for return
  • If told the module "won't program," contact us before returning
  • Defective units replaced ONLY ONCE, under warranty

ℹ️ Product Notes

This is a used part. It is the main Engine Control Module (ECM). This module ran well before it was removed. This part is for vehicles built starting in August. It does not have the high speed synchronization feature. Note: This computer module may need to be reprogrammed by a service center. Modules can only be reprogrammed a limited number of times.

This part must be programmed to your car by a professional. It only fits cars built after August 2003. Check the sticker on your driver's door for the build date.
Condition: Excellent (A)
Like new, minimal to no wear
86,810 miles
Odometer reading when part was removed
See Other BMW Z4 Engine Control Module (ECM)s
SKU #
3949701-03906-095

Why Buy Used OEM Parts?

✓ Quality-Verified: Every used OEM part we sell has been professionally inspected and tested to ensure it meets our quality standards. While it may show some cosmetic wear from previous use, it's fully functional and ready to install.

✓ Original Equipment: This is a genuine OEM (Original Equipment Manufacturer) part - the exact same part that came with your vehicle from the factory. It's designed specifically for your make and model, ensuring perfect fitment and performance.

✓ Works Like New: Despite some visual wear, this part will perform just as well as a brand new one. The internal components and functionality are intact, giving you the same reliability you'd expect from OEM quality.

✓ Significant Savings: Save 50-80% compared to buying new! Used OEM parts offer exceptional value - you get factory quality at a fraction of the cost. It's the smart choice for budget-conscious vehicle owners who won't compromise on quality.

✓ Risk-Free Purchase: We stand behind our used parts with a generous 6-month warranty, 30-day returns, and 100% money-back guarantee. If it doesn't work out for any reason, simply return it for a full refund. You have nothing to lose!

🛡️ 30-Day Returns + 6-Month Warranty - Buy with Confidence!

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Vehicle Fitment Guide

This part fits the following vehicles:

BMW
Z4 2003-2005 (tapclick to expand)(tapclick to hide)
Swipe left/right to see more info
SubmodelSUB-
MODEL		 Body Style Years Engine Attributes
2.5i Convertible 2003 - 2005 L6 2.5L RWD | Automatic & Manual | Fits models built after August 2003
3.0i Convertible 2003 - 2005 L6 3.0L RWD | Automatic & Manual | Fits models built after August 2003
2004

⚠️ Important: Please verify your vehicle's year, make, model, and specifications before ordering. If you're unsure about fitment, contact our customer service team for assistance.

Policies

Shipping & Handling

  • Standard shipping: 3-7 business days via UPS Ground
  • Parts are carefully packaged to prevent damage during transit

Returns (30 Days)

We accept returns within 30 days of delivery for this part.

  • Defective parts: We will replace the part or issue a refund at our discretion
  • Electronic parts: Must be returned with the sealed inspection bag unopened. The clear bag allows full visual inspection before opening. Once opened, electronic parts can only be exchanged for a replacement if defective — no refunds
  • Programming: "Needs to be programmed to my vehicle" is not a valid return reason. Many modules require dealer programming — we're happy to help connect you with resources if your dealer says it's not programmable
  • Return shipping: We cover return shipping as part of our 100% money-back guarantee
  • Parts must be returned in original packaging and unmodified condition
  • Poorly packaged returns that arrive damaged will not be credited

6-Month Warranty

All used parts include a 6-month warranty from the date of purchase.

  • If your part fails within 6 months, we will send a replacement
  • Refunds are only issued if we cannot provide a suitable replacement
  • Warranty covers defects — not installation errors, misuse, or damage after installation

Note: Warranty is for replacement, not refund. A part failing on day 80? We'll replace it. But the return window for refunds is 30 days.

Damaged in Shipping?

If your part arrives damaged:

  • Stop immediately — do not install the part
  • Keep all original packaging and boxes
  • Take clear photos of the damage and packaging
  • Contact us within 48 hours of delivery

We will handle the carrier claim. You are not responsible for shipping damage — we just need your help documenting it.

Order Cancellation

Orders can be cancelled before shipment for a full refund. Once shipped, cancellations follow our return policy.

Symptoms & Diagnosis

Warning Signs of a Failing Engine Control Module (ECM)

  • Engine misfires or runs rough
  • Stalling or difficulty starting
  • Check Engine Light is on
  • Poor fuel economy
  • Transmission shifting problems
  • Car won't start at all

How to Test if the ECM is the Problem

  1. Check the basics: Make sure the battery is good, the spark plugs are firing, and there are no vacuum leaks.
  2. Scan for codes: Use an OBD-II scanner to read the trouble codes stored in the ECM. This can help pinpoint the problem.
  3. Inspect wiring: Check the wiring harness and connectors for any damage, corrosion, or loose connections.
  4. Consult a mechanic: A qualified mechanic can perform more advanced tests to diagnose the ECM.

Common Failure Causes

  • Overheating
  • Voltage spikes
  • Water damage
  • Physical damage
  • Age and wear

Buyer's Checklist

What to Look For When Buying

  • Compatibility: Verify the ECM is designed for your specific vehicle year, make, and model.
  • Condition: If buying a used ECM, check for any signs of damage or corrosion.
  • Warranty: Look for a warranty to protect your investment.
  • Reputation: Buy from a reputable seller.

Quality Indicators

FeatureUsed OEMNew Aftermarket
SourceOriginal equipment from the manufacturerThird-party manufacturer
TestingTypically tested and inspectedNew, but may not have been tested in a vehicle
ReliabilityGenerally reliable, as it's a factory partCan vary depending on the manufacturer
PriceLower than new aftermarketHigher than used OEM

What's Typically Included

  • The ECM itself
  • Sometimes, installation instructions (check with the seller)

Installation Overview

Difficulty Level and Estimated Time

  • Difficulty: Medium
  • Estimated Time: 1-3 hours

Special Tools Needed

  • Basic hand tools (sockets, wrenches, screwdrivers)
  • OBD-II scanner
  • Possibly a code reader/programmer (depending on the vehicle and ECM)

Critical Steps and Tips

  1. Disconnect the battery: This is crucial for safety.
  2. Locate the ECM: It's usually under the hood or under the dashboard.
  3. Disconnect the wiring harness: Be careful not to damage the connectors.
  4. Remove the old ECM: Unbolt it from its mounting bracket.
  5. Install the new ECM: Bolt it in place and reconnect the wiring harness.
  6. Reconnect the battery:
  7. Program the ECM: Some ECMs need to be programmed to your vehicle. This may require a specialized tool or a trip to a mechanic.

DIY or Professional Installation?

  • DIY is possible if you have mechanical experience and the necessary tools.
  • Professional installation is recommended if you're not comfortable working on your car or if the ECM needs to be programmed.

Buying Options

Compare: Used OEM, New Aftermarket

FeatureUsed OEMNew Aftermarket
ProsGenuine factory part, tested and inspected, lower price, reliable (as it's a factory part)Brand new, readily available
ConsMay have some wear and tear, availability may be limitedQuality can vary, may not be as reliable as OEM
Best ForBudget-conscious buyers who want a reliable replacement part.Buyers who prefer a brand new part and don't mind paying a bit more.

Used OEM

  • Best value for your money.
  • Genuine factory parts, ensuring proper fit and function.
  • Tested and inspected to ensure they're working properly.
  • Significantly lower prices than new parts.

New Aftermarket

  • Brand new parts from third-party manufacturers.
  • Built to meet or exceed OE specifications.
  • A good option if you prefer a new part.

Typical Lifespan

How Long This Part Normally Lasts

  • An ECM can last for the life of the vehicle, often 10-15 years or more.

Factors That Affect Longevity

  • Overheating
  • Voltage spikes
  • Water damage
  • Physical damage
  • Proper maintenance

Price Ranges

Budget vs Mid-Range vs Premium Options

  • Used OEM: $150 - $350
  • New Aftermarket: $300 - $600

Labor Cost Considerations

  • Labor costs can vary depending on the mechanic and the complexity of the job.
  • Expect to pay $100 - $300 for labor.

Total Job Cost Estimates

  • Used OEM: $250 - $650 (parts and labor)
  • New Aftermarket: $400 - $900 (parts and labor)

Vehicle-Specific Notes

Known Issues

  • Some models have issues with the ECM due to heat.
  • Check engine light issues related to O2 sensors can sometimes be related to the ECM.

TSBs or Common Complaints

  • Check for any Technical Service Bulletins (TSBs) related to the ECM on your specific vehicle.
  • Common complaints include intermittent stalling and misfires.

Verification After Install

How to Confirm Proper Operation

  • Start the engine and let it idle.
  • Check for any unusual noises or vibrations.
  • Drive the car and see how it performs.
  • Use an OBD-II scanner to check for any new trouble codes.

What to Look/Listen For

  • Smooth engine operation
  • Proper shifting
  • No Check Engine Light
  • Good fuel economy

FAQ

Q: Will this ECM need to be programmed?
A: Some ECMs need to be programmed to your vehicle's VIN. Check with the seller or a mechanic to see if programming is required.

Q: How do I know if my ECM is bad?
A: Common symptoms include engine misfires, stalling, difficulty starting, and a Check Engine Light.

Q: Can I install this ECM myself?
A: Yes, if you have mechanical experience and the necessary tools. However, professional installation is recommended if you're not comfortable working on your car.

Q: What if the ECM I receive is defective?
A: Buy from a seller with a good return policy.

Q: How can I prevent my ECM from failing again?
A: Address any underlying issues that may have caused the original ECM to fail, such as overheating or voltage spikes.

Part Specifications

OEM Part Numbers:

  • BMW: 12147527015, 12147533652, 12147549095, 12147549133, 12147549390, 12147561383, 7549095

Fits Years: 2003 2004 2005

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