MERCEDES Acceleration Control Module 591.MB1Y91 Benz 1295450132 R277084

( Part Type: Control Module ), ( Conditions Options: Asr Accelration Cntrl Mod ), ( Genuine Oem: Yes ), ( Ipn: 591.mb1y91 ), ( Make: Mercedes-benz ), ( Programming Required: No ), ( Country Of Origin: Germany ), ( Manufacturer Warranty: N.a. ), ( California Prop 65 Warning: California Prop 65 Warning )

Review MERCEDES benz Acceleration Control Module fits 500SL 1991

The **Mercedes-Benz 591.91 MB1Y91 1991 500SL Acceleration Control Module (Part Number: 1295450132, R277084)** is a precision-engineered electronic component integral to the performance and refinement of one of the most iconic luxury roadsters of the late 20th century. Originally designed for the legendary **1991 Mercedes-Benz 500SL (W129)**, this acceleration control module plays a critical role in managing the vehicle s throttle response, ensuring smooth and controlled power delivery while enhancing driving dynamics. As part of the **MB1Y91** engine management system, this module interfaces directly with the engine control unit (ECU) to regulate acceleration rates, preventing abrupt power surges that could compromise handling or passenger comfort. Crafted to Mercedes-Benz s exacting standards, the module features robust internal circuitry with high-quality resistors, capacitors, and semiconductor components, all housed in a durable, corrosion-resistant enclosure designed to withstand the demanding conditions of high-performance driving.

The **1295450132** module is specifically tailored for the **500SL s 5.0-liter V8 engine**, which produces a commanding 231 horsepower and 292 lb-ft of torque in its base form, making it a standout in its class. This module ensures that the engine s throttle response is calibrated to the vehicle s suspension, steering, and braking systems, allowing for a seamless transition between acceleration and cruising. Over time, wear and tear, electrical fluctuations, or exposure to moisture can degrade the module s performance, leading to erratic throttle behavior, hesitation, or even complete failure. Replacing it with an **OEM R277084** part guarantees that the 500SL retains its signature blend of power and elegance, restoring factory-intended responsiveness and reliability.

Beyond its functional role, this module is a testament to Mercedes-Benz s engineering heritage, embodying the brand s commitment to blending cutting-edge technology with timeless luxury. Whether restoring a classic 500SL to its original glory or maintaining a well-loved collector s car, this **1295450132 acceleration control module** ensures that every drive is as refined as it is exhilarating. Its compatibility with aftermarket tuning systems further underscores its versatility, allowing enthusiasts to fine-tune throttle characteristics for enhanced performance without compromising the vehicle s iconic character. For owners seeking to preserve the soul of their Mercedes-Benz 500SL, this module is an essential component one that bridges the gap between mechanical precision and driving pleasure.

### **Analysis of Buying a 1991 Mercedes-Benz 500SL (W126) with Acceleration Control Module (Part #1295450132, R277084)**

#### **Overview of the Vehicle**

The 1991 Mercedes-Benz 500SL (W126) is a classic luxury grand tourer with a 5.0L V8 engine (M117) producing around 250 280 hp, depending on modifications. The **acceleration control module (part #1295450132, R277084)** is an electronic component that regulates throttle response, often used in performance tuning or as a replacement for a faulty stock system.

---

### **Pros of Purchasing This Part**

1. **Performance Enhancement**

- The acceleration control module can improve throttle response, making the engine more responsive, especially in high-performance applications.

- Some aftermarket modules allow for adjustable power delivery, which can be useful for tuning or restoring stock-like behavior.

2. **Compatibility with Tuning**

- If the vehicle is being modified (e.g., with a tune, forced induction, or performance exhaust), this module can help manage throttle control under increased power demands.

- Some modules integrate with modern ECU tuning systems, allowing for precise adjustments.

3. **Potential for Restoring Stock Functionality**

- If the original acceleration control module is faulty (common in older W126 models), replacing it with an OEM or high-quality aftermarket unit can restore proper throttle control.

- Some aftermarket modules are designed to mimic stock behavior, which can be beneficial for restoration projects.

4. **Availability of Aftermarket Support**

- Many aftermarket suppliers offer compatible modules with warranties, making it easier to find replacements than original Mercedes parts.

- Some modules come with diagnostic tools to help troubleshoot throttle-related issues.

5. **Potential for Increased Reliability**

- If the original module was failing intermittently (e.g., stalling, hesitation, or erratic throttle response), a new module can eliminate these issues.

- Some modules include fail-safe features to prevent complete loss of throttle control.

---

### **Cons of Purchasing This Part**

1. **Compatibility Issues**

- The W126 500SL (especially pre-1992 models) may require additional modifications to work seamlessly with modern or aftermarket acceleration control modules.

- Some modules may not be fully compatible with stock ECUs, leading to calibration or programming requirements.

2. **Cost vs. Benefit**

- While aftermarket modules are often cheaper than OEM replacements, they may not offer the same level of reliability or longevity.

- If the vehicle is not being tuned, the benefits of an aftermarket module may be minimal compared to a simple throttle body or ECU replacement.

3. **Potential for Voiding Warranties (If Applicable)**

- If the vehicle is under warranty (unlikely for a 1991 model), installing aftermarket electronic components could void coverage.

- Some aftermarket modules may not be officially supported by Mercedes-Benz, leading to potential compatibility risks.

4. **Installation Complexity**

- Replacing or installing an acceleration control module may require wiring knowledge, as it often connects to the ECU, throttle body, and sometimes other sensors.

- Incorrect installation can lead to electrical issues, such as short circuits or improper sensor readings.

5. **Limited Long-Term Data**

- Since the W126 is an older model, long-term reliability data on aftermarket acceleration control modules may be scarce.

- Some modules may degrade over time, requiring replacement or recalibration.

6. **Possible Overkill for Stock Applications**

- If the vehicle is not being modified, the stock throttle system may already function adequately, making the upgrade unnecessary.

- Adding an acceleration control module without tuning may not provide noticeable benefits.

---

### **Conclusion**

- Tuning the engine for increased power.

- Restoring throttle control in a vehicle with electrical issues.

- Looking for a more responsive throttle system in a modified setup.

However, if the vehicle is running stock or you are not planning modifications, the benefits may not justify the cost or complexity. Additionally, compatibility and installation risks must be carefully considered.

---

### **Recommendation**

- Purchase a **high-quality aftermarket acceleration control module** (e.g., from brands like **Megajolt, Haltech, or AEM**) that is known for compatibility with the W126.

- Consult with a **Mercedes specialist or tuning shop** to ensure proper integration with the ECU and throttle system.

- Consider pairing it with a **performance tune** for optimal results.

- Verify that the original module is indeed faulty (test with a multimeter or diagnostic tool).

- If the issue is electrical (e.g., bad wiring, faulty throttle position sensor), address those first before replacing the module.

- An **OEM replacement** (if available) may be more reliable than aftermarket options.

- The acceleration control module may not be necessary unless you experience specific throttle-related issues.

- Focus on maintaining the stock ECU and throttle system rather than upgrading.

- Research **user reviews and forums** (e.g., W126 forums, Mercedes-Benz clubs) for experiences with this specific part.

- If unsure about installation, hire a **qualified mechanic** with experience in Mercedes electronic systems.

- Ensure the module is **properly grounded and wired** to avoid electrical issues.

The part is **worth considering for tuning or restoration projects**, but it is **not essential for stock operation**. Always weigh the potential benefits against the cost, installation difficulty, and compatibility risks before purchasing.

Details:

Specializing in used parts for: Audi, Land Rover, Mercedes-Benz, Volkswagen. Help Message.

part #: 500sl prices

• $119.00-$749.99

specifications pedalspadsaz:

• for models: 500sl
• for makes: Mercedes
• for years: 1991
• part type: Control Module
• conditions options: Asr Accelration Cntrl Mod
• genuine oem: Yes
• ipn: 591.mb1y91
• make: Mercedes-benz
• programming required: No
• country of origin: Germany
• manufacturer warranty: N.a.
• california prop 65 warning: California Prop 65 Warning

general pedalspadsaz:

• Car Truck Parts Accessories > Starters, Alternators, ECUs Wiring > ECUs Computer Modules
• condition: Used

seller pedalspadsaz:

• # reviews: 1984
• city: Rancho Cordova, California
• rating: 100.0%

returns pedalspadsaz:

• time: 30 Days
• policy: Returns Accepted
• paid by: Buyer

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• other
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• wallet: Apple-pay

offer pedalspadsaz:

• started: March 12, 2026
• options: Ship-to-home
• availability: In Stock
• quantity: 1
• sold: 0
• best offers: True

shipping pedalspadsaz:

• cost: $23.00
• type: Fixed
• transit: 2-6 Days
• class: Standard, Expedited, One-day
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