P1587 Code: Meaning, Symptoms, Causes & Fix

Overview

Symptoms

• occasional limp mode
• poor throttle response
• engine feels underpowered

Common causes

• Component failure in the monitored system affecting throttle control unit modulated command malfunction
• Control module logic or calibration issue
• Connector pin damage/corrosion or harness stress near related components

How to diagnose P1587

1. Confirm P1587 and capture freeze-frame data with a professional scan tool.
2. Inspect wiring, connectors, and grounds related to throttle control unit modulated command malfunction for obvious defects.
3. Use freeze-frame and live data to isolate whether the issue is electrical, mechanical, or control logic.
4. Check for related DTCs to identify the root-cause chain before replacing parts.
5. After repair, clear codes and confirm readiness monitors complete without recurrence.

Severity of code P1587

Low: This code is low to moderate severity in most cases, but diagnosis is still recommended to avoid recurring warnings.

Can you drive with P1587?

The vehicle is often drivable with P1587, but plan a repair window to prevent repeat faults.

If the warning lamp is flashing or drivability/safety is affected, avoid driving and diagnose immediately.

How to fix it (step-by-step)

1. Repair obvious wiring/connector faults first to prevent repeat parts replacement.
2. Address the root fault mode (generic) in the throttle control unit modulated command malfunction circuit/system.
3. Apply the required relearn/adaptation procedure if specified by service information.
4. Road-test and verify P1587 remains cleared under the conditions that originally set the code.

Fix options

• Clear code and confirm through drive cycle.
• Test component operation and replace if faulty.
• Clear DTCs and verify with live data and completed drive cycle.

Typical repair cost

$100-$450

Common mistakes when diagnosing P1587

• Replacing parts without verifying voltage, ground, and signal integrity first.
• Ignoring related stored/pending codes that indicate upstream faults.
• Skipping post-repair verification drive cycle and readiness checks.

P1587 in common vehicles

P1587 appears across makes such as BMW, Mercedes-Benz, Audi, Volvo. Failure patterns differ by platform: wiring routes, software calibration, and component supplier revisions can change root cause.

Frequently asked questions

What causes P1587?

P1587 is commonly set by generic faults affecting throttle control unit modulated command malfunction.

How much does it cost to fix P1587?

For P1587, repair costs are typically $100-$450 depending on exact root cause, labor rates, and part quality.

Can I clear P1587 without repair?

You can clear P1587 temporarily, but the code usually returns until the underlying fault is corrected.

Helpful tools

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