AutoCodes – Jeep – U1421 Jeep

U1421 Jeep Code - Implausible Ignition Key Off Time Received

Quick Answer

The Body Control Module (BCM) monitors the time the ignition is in the off or accessory position between key cycles and then broadcasts the signal called Ignition Off Time (IOT) via the CANC Bus. Common causes include Faulty Body Control Module (BCM), Body Control Module (BCM) harness is open or shorted, Body Control Module (BCM) circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: U1421 Jeep indicates Implausible Ignition Key Off Time Received.
Common causes: Common causes include Faulty Body Control Module (BCM), Body Control Module (BCM) harness is open or shorted, Body Control Module (BCM) circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 1,420

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 23, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1421 Jeep Description

The Body Control Module (BCM) monitors the time the ignition is in the off or accessory position between key cycles and then broadcasts the signal called Ignition Off Time (IOT) via the CANC Bus. The Powertrain Control Module (PCM) saves the value from a previous key cycle into powerdown flash and if certain When Monitored conditions are met compares to the current value. If the Set Conditions are met, then a fault U1421 is set indicating the timer is stuck. If this fault becomes active the PCM will light the MIL light immediately. If the MIL is set and the fault goes stored the PCM turns off the MIL after 3 consecutive drive cycles. If the difference between two Ignition Off Times (IOT) sent from the BCM to the PCM during two separate diagnostic decisions is less than 3 minutes for 5 consecutive decisions this fault will set.

OBDII Code U1421 Jeep - Implausible Ignition Key Off Time Received - AutoCodes.com — U1421 Jeep Code - Implausible Ignition Key Off Time Received

What does this mean?

What are the Possible Causes of the DTC U1421 Jeep?

Faulty Body Control Module (BCM)
Body Control Module (BCM) harness is open or shorted
Body Control Module (BCM) circuit poor electrical connection
Faulty Powertrain Control Module (PCM)

How to Fix the DTC U1421 Jeep?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U1421 Jeep code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the U1421 Jeep code?

Need more information on how to fix the U1421 Jeep code? Get Access to Factory Service Manuals

Need Help with the Code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about U1421 Jeep Code

1. What does the OBDII code U1421 for Jeep mean?

The code U1421 indicates an issue with the ignition key off time received being implausible, meaning the vehicle's computer has detected an error in the key-off time data.

2. What are the common symptoms of the U1421 code in a Jeep?

Common symptoms of the U1421 code may include the engine stalling or running rough, problems starting the vehicle, and the Check Engine Light illuminating on the dashboard.

3. What are the possible causes of the U1421 code in a Jeep?

Possible causes of the U1421 code include a faulty ignition switch, issues with the keyless entry system, a malfunctioning immobilizer system, or wiring problems in the ignition key circuit.

4. How do you diagnose the U1421 code in a Jeep?

Diagnosing the U1421 code typically involves using an OBDII scanner to retrieve the code and then performing a thorough inspection of the ignition key system, including checking for any loose connections or damaged wiring.

5. Can I still drive my Jeep with the U1421 code present?

It is not recommended to drive your Jeep with the U1421 code present, as it can lead to potential issues with starting the vehicle or engine performance.

6. How do you repair the U1421 code in a Jeep?

Repairing the U1421 code may involve fixing any underlying issues with the ignition key system, such as replacing a faulty ignition switch, repairing wiring problems, or reprogramming the keyless entry system.

7. Can the U1421 code be cleared without fixing the underlying issue?

While you can clear the U1421 code with an OBDII scanner, it is essential to address the root cause of the problem to prevent it from reoccurring.

8. Is the U1421 code specific to certain Jeep models?

The U1421 code is commonly associated with Jeep vehicles, particularly models equipped with keyless entry systems and immobilizers.

9. How much does it typically cost to repair the U1421 code in a Jeep?

The cost of repairing the U1421 code can vary depending on the underlying issue, but it may range from around $100 to $500, including parts and labor.

10. Can I prevent the U1421 code from occurring in the future?

To prevent the U1421 code from occurring in the future, regular maintenance of the ignition key system, such as keeping key fobs in good condition and checking for any wiring issues, can help avoid potential problems.