2024 Jeep Wrangler Hybrid System Warning TSB S2408000063

Owners of the 2024 Jeep Wrangler 4xe may encounter a specific issue where a "Service Hybrid Electric Vehicle System Warning" message and light are displayed on the instrument cluster. This condition is often accompanied by the vehicle's inability to enter Electric or Hybrid drive modes. When scanned, the Hybrid Control Processor (HCP) will typically show the diagnostic trouble code (DTC) B273C-00, indicating a "Digital Crash Input Set In HCP."

Symptoms

If your 2024 Jeep Wrangler hybrid system warning is active, you will observe the following:

• A "Service Hybrid Electric Vehicle System Warning" message displayed in the cluster.
• An associated warning light illuminated on the dashboard.
• The vehicle may be unable to engage Electric or Hybrid drive modes, operating solely on the Internal Combustion Engine (ICE) in E-Save mode.

Fault Codes / DTCs

The primary diagnostic trouble code associated with this issue is:

• B273C-00: Digital Crash Input Set In HCP

This code indicates that the Hybrid Control Processor (HCP) has detected an invalid or corrupted digital crash input signal.

Diagnosis / Trigger Conditions

The root cause of the 2024 Jeep Wrangler hybrid system warning and DTC B273C-00 is electromagnetic interference (EMI). This EMI originates from the High Voltage (HV) P2 Motor and its associated HV harnesses. This interference can transfer inductive voltage or electrical noise onto the R41 (Airbag Deployment Signal) and R414 (Airbag Deployment Signal 2) circuits. This electrical noise corrupts the health status signal, leading to the B273C-00 DTC.

To diagnose this, technicians are advised to connect an oscilloscope, such as the Mopar PicoScope, to the R41 and R414 circuits. When the P2 motor engages, a distinctive change in the voltage pattern indicating induction voltage or electrical noise will be visible. While some EMI is normal, excessive levels will cause the B273C-00 code to set.

Important Warnings

• Airbag System Safety: ORC Engineering has confirmed that airbag deployment and operation are NOT compromised by this fault or its setting conditions. The vehicle can be safely released to the customer.
• Drive Mode Limitation: As long as the B273C-00 – Digital Crash is active, the "Service Hybrid Electric Vehicle System Warning" message and Malfunction Indicator Lamp (MIL) will continue to be displayed. The vehicle will only operate using the Internal Combustion Engine (ICE), also known as E-Save mode; Electric and Hybrid drive modes will be inoperative.
• Warranty Repairs: This document does not authorize warranty repairs. Any component replacements mentioned are for mitigating buyback risk and are at the dealer's discretion, not guaranteed repairs.

Repair Procedure Summary

A comprehensive solution for the 2024 Jeep Wrangler hybrid system warning is expected to be released in the form of a Technical Service Bulletin (TSB) or Rapid Service Update (RSU) in Q4 2024. This future repair will involve:

• Software Update: An update to the HCP, AHCP, and PCM software. This update will enhance the HCP's ability to correctly detect a valid Digital Crash Input health signal even when excessive EMI is present.
• Wiring Harness Repair: A specific wiring harness repair designed to eliminate excessive EMI.

For vehicles at high risk of buyback, validated flash files are currently available. Technicians should contact their Tech Advisor (TA) directly or via STAR escalation. The FTS electrical team can provide VIN-specific flash files to the TA, which can then be flashed to the appropriate modules using CDA.

Potential Component Replacements (for Buyback Risk Mitigation Only)

For vehicles facing buyback, replacing certain components has been found to lower EMI to an acceptable level on some vehicles. It is crucial to understand that replacement of these components does not guarantee repair and should only be performed to mitigate buyback risk, not as a warranty repair. These replacements should be done one at a time, verifying if the concern is resolved before proceeding to the next component.

1. BPCM to Battery Coolant Heater HV Harness: Part Number 68593178AC
2. P2 to PIM HV Harness: Part Number 68593176AB
3. P1 to PIM HV Harness: Part Number 68593175AB
4. BPCM to IDCM HV Harnesses: Part Number 68378608AF
5. Occupant Restraint Controller (ORC)

Owners should always verify the most current part number using their vehicle's VIN in STAR parts.

What Owners Should Do

If your 2024 Jeep Wrangler is displaying the "Service Hybrid Electric Vehicle System Warning" message and exhibiting the described symptoms, contact your authorized Jeep dealer. While the vehicle can be safely driven in E-Save mode, the full repair is pending the release of the TSB/RSU in Q4 2024. Discuss the specific symptoms and any diagnostic codes with your service advisor.

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Source: NHTSA ID: 11008974