Recall 21V181 affects 1 2021 Peterbilt 536 vehicle for incorrect engine control module calibration. The affected vehicle was repaired by March 3, 2021.
Peterbilt is recalling 1 2021 536 vehicle under recall 21V181 because incorrect engine control module calibration can prevent engine speed and torque limits from working as intended for braking, traction, stability, speed control, or collision avoidance. If those safety-related functions do not work properly, crash risk increases, and Peterbilt dealers will complete the repair free of charge.
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What's wrong?
The engine control module on the 2021 Peterbilt 536 with a Cummins B6.7N engine is the computer that manages engine behavior. It reads signals from the truck and other control systems, then commands fuel and engine output. For safety-related functions, that software is supposed to limit engine speed or torque when braking, traction control, stability control, speed control, or collision avoidance needs reduced power.
On the recalled truck, the module has an incorrect software calibration. A calibration is the set of instructions that tells the engine computer how to respond in specific conditions. Because this calibration is wrong, the engine does not limit speed or torque as intended when those safety systems request it.
There is no warning sign before failure. The truck can feel normal until a safety-related function asks the engine to reduce output and the software does not respond correctly.
Who's affected?
Both listed components point to the same Cummins B6.7N engine: engine software and the engine itself.
| 2021 Peterbilt 536 | Software |
|---|---|
| 2021 Peterbilt 536 | Engine |
| Units affected | 1 |
| Field incidents | NHTSA has logged no field incidents to date. |
A matching year and model does not guarantee inclusion. Check your VIN to confirm whether this recall applies to your specific truck.
What's the safety risk?
If braking, stability, speed, or collision-avoidance functions fail to work properly, the truck is harder to control and crash risk rises. If your VIN is included, limit use and schedule the dealer repair now. Repair is free at any franchised Peterbilt dealer.
What should I do?
- Check your VIN to confirm your 2021 Peterbilt 536 is included in this recall.
- Contact a franchised Peterbilt dealer to confirm the free engine control module software update is complete.
- Ask the dealer to verify that the update restores the intended engine speed and torque limits for braking, traction, stability control, speed control, and collision avoidance.
- Bring the recall notice if Peterbilt mailed one. If not, reference recall number 21V181 when you call.
- Call Peterbilt customer service at 1-940-591-4220 with questions about the repair record.
What happens at the repair
PACCAR reported that it owned the affected 2021 Peterbilt 536 and that the recall repair was completed on March 3, 2021. The repair was a software update to correct the engine control module calibration so the engine speed and torque limits work as intended with braking, traction control, stability control, speed control, and collision avoidance functions. Parts and labor are covered under the recall. PACCAR has a general reimbursement plan on file for documented out of pocket costs tied to this recall. Contact PACCAR customer service with any prior repair paperwork.
| Reimbursement | Reimbursement available |
|---|
Timeline
| March 3, 2021 | Owner notification mailed |
|---|---|
| March 16, 2021 | NHTSA published the recall |
Frequently asked questions
What is recall 21V181?
Recall 21V181 covers 1 2021 Peterbilt 536 with Cummins Westport B6.7N engine control module software calibrated incorrectly. The error can prevent the engine from limiting speed or torque for braking, traction, stability, speed control, or collision avoidance functions, increasing crash risk.
What should I do if my 2021 Peterbilt 536 is on this recall?
Check your VIN to confirm whether your specific vehicle is included in recall 21V181. If it is, contact a franchised Peterbilt dealer or PACCAR customer service at 1-940-591-4220 and reference PACCAR recall number 21PBC. PACCAR reported the affected vehicle was repaired on March 3, 2021.
Is the recall repair free?
Yes. Federal recall law requires the manufacturer to repair the defect at no cost. PACCAR reported that it owned the affected 2021 Peterbilt 536 and completed the repair on March 3, 2021.
What is the safety risk?
The safety risk is loss of proper support from braking, stability, speed, and collision avoidance functions. If the engine control module does not limit speed or torque as intended, those safety-related systems can fail to function properly, increasing crash risk.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/21V181000 |
|---|---|
| Peterbilt customer service | 1-940-591-4220 |
| NHTSA recall # | 21V181 |
| NHTSA recall # (full) | 21V181000 |
Source documents
This article is generated from NHTSA's primary recall filings and reviewed against the source on May 23, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →