Jeep U1124-00
Use wiTECH to verify the HV coolant heater status. The ECH status can be found in the Hybrid Control Processor (HCP) under the data tab. The status will be one of the following: -
Common search variants: U112400 · U1124 00 · U1124_00 · Search ignores case and common separators.
Quick answer
For a 2021–2022 Jeep Wrangler in the U.S., U1124-00 is addressed in an official Jeep service communication concerning HV coolant-heater diagnosis. Use wiTECH to check the ECH status in the Hybrid Control Processor (HCP) Data tab. The supplied evidence says OFF indicates normal ECH operation.
This page separates verified manufacturer/regulator evidence from supporting material. Unsupported causes, repairs or safety conclusions are not guessed.
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1. What does U1124-00 mean?
For a 2021–2022 Jeep Wrangler in the U.S., U1124-00 is addressed in an official Jeep service communication concerning HV coolant-heater diagnosis. Use wiTECH to check the ECH status in the Hybrid Control Processor (HCP) Data tab. The supplied evidence says OFF indicates normal ECH operation.
2. Technical explanation
The verified NHTSA-hosted manufacturer communication instructs technicians to assess and resolve contributing low-voltage, high-voltage, and heater high-voltage-supply issues before replacing the heater. It warns that failure to resolve the contributing condition can lead to repeat heater failure and a return visit. The communication specifically directs use of wiTECH to verify HV coolant-heater status through the HCP Data tab.
3. What system is affected?
HV coolant heater / ECH status as monitored in the Hybrid Control Processor (HCP).
4. How serious is this code?
Not yet established by verified evidence.
5. Symptoms you may notice
Not yet established by verified evidence.
6. Possible causes
- The official communication says contributing low-voltage system, high-voltage system, and heater high-voltage-supply issues must be assessed and resolved before heater replacement.
- For intermittent concerns, the communication directs cleaning and securing involved system-component grounds.
7. Can I still drive the vehicle?
Not yet established by verified evidence.
8. Can I charge the vehicle?
Not yet established by verified evidence.
9. What you can safely do
- Arrange diagnosis by a qualified Jeep service facility with wiTECH capability.
- Do not replace the HV coolant heater solely on the basis of this code without diagnosis of contributing conditions.
- Do not perform high-voltage repair work yourself.
10. Step-by-step troubleshooting
- A service technician should perform published diagnostics for applicable low-voltage and high-voltage system DTCs, including U1008-00 and/or U1124-00, as directed by the official communication.
- Using wiTECH, check ECH status in the HCP Data tab.
- The supplied evidence states that an ECH status of OFF means ECH operation is normal; the remaining listed status definitions are not included in the supplied evidence.
- For an intermittent concern, clean and secure the involved system-component grounds, as directed by the communication.
11. When to contact service
Service involvement is appropriate because the verified procedure requires wiTECH and includes high-voltage-system diagnostics.
12. What the service center may check
- Read all applicable low-voltage and high-voltage system DTCs.
- Check U1008-00 and/or U1124-00 as part of the published diagnostic process.
- Verify ECH status using wiTECH in the HCP Data tab.
- Assess heater high-voltage-supply issues before heater replacement.
- For intermittent concerns, inspect the involved component grounds and clean and secure them as directed.
13. Possible repair or resolution
- Resolve identified contributing low-voltage, high-voltage, or heater high-voltage-supply conditions before replacing the heater.
- For intermittent concerns, clean and secure involved system-component grounds.
- Heater replacement may be considered only after the contributing condition is addressed; detailed replacement criteria are not established by the supplied evidence.
14. Affected vehicles
- Jeep Wrangler · 2021–2022 · US
15. Related TSBs / service bulletins
- NHTSA Manufacturer Communication PDF 10229484, S2208000027RevA, published August 12, 2022. It covers diagnosis related to HV coolant-heater status and directs wiTECH review of ECH status in the HCP Data tab.
16. Recall information
No recall relationship is established by verified evidence.
17. Official manufacturer information
Verified source: NHTSA-hosted Jeep manufacturer communication S2208000027RevA, document MC-10229484-9999.pdf. Applicability supplied with this record: 2021–2022 Jeep Wrangler, U.S. Confirm applicability to the individual vehicle with a Jeep dealer or VIN-based service lookup.
19. Frequently asked questions
What does OFF ECH status mean for U1124-00?
The supplied official communication states that OFF means ECH operation is normal.
Where is the ECH status checked?
The communication directs use of wiTECH, with ECH status located in the Hybrid Control Processor (HCP) under the Data tab.
Should the HV coolant heater be replaced immediately?
No. The communication says contributing low-voltage, high-voltage, and heater high-voltage-supply issues must be assessed and resolved before heater replacement.
Does this evidence confirm that the vehicle is safe to drive or charge?
No. Driveability and charging safety are not yet established by verified evidence.