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P0155 on Jeep Grand Cherokee

O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)

Factory diagnostic protocol and troubleshooting wire for fault code P0155 specifically for the Jeep Grand Cherokee (2021–2026, 3.6L Pentastar V6 (293HP) / 5.7L HEMI V8 / 4xe PHEV (375HP)).

Verified OEM Telemetry & Field Repair Tree
Jeep Grand Cherokee2021–2026
Jeep Grand Cherokee
SUV3.6L Pentastar V6 (293HP) / 5.7L HEMI V8 / 4xe PHEV (375HP)
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
Grand Cherokee SAE Mode $01
ECU Network Bus
500 kbps CAN-FD
ISO 15765-4 Compliant
Drivability Status
Drivable (Short Trip)
Medium urgency level
Est. Repair Cost
$120 - $350 (DIY: $45 - $120)
Parts & Labor DIY
Check P0155 On Another Jeep Model:
Diagnose P0155 on Specific Grand Cherokee Model Year:

1. Symptoms of P0155 on Jeep Grand Cherokee

When the Engine Control Module (ECM/PCM) on your Jeep Grand Cherokee (3.6L Pentastar V6 (293HP) / 5.7L HEMI V8 / 4xe PHEV (375HP)) logs fault code P0155, drivers commonly observe:

Check Engine Light on immediately after cold start on Jeep Grand Cherokee (3.6L Pentastar V6 (293HP) / 5.7L HEMI V8 / 4xe PHEV (375HP))
Slightly increased cold-start emissions on Jeep Grand Cherokee (3.6L Pentastar V6 (293HP) / 5.7L HEMI V8 / 4xe PHEV (375HP))
No major driving performance issues once engine reaches full operating temperature on Jeep Grand Cherokee (3.6L Pentastar V6 (293HP) / 5.7L HEMI V8 / 4xe PHEV (375HP))
Jeep Grand Cherokee OBD-II Port Location
The 16-pin diagnostic connector is located Under driver side dashboard above foot pedals. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Jeep Grand Cherokee

Historical warranty claims and technical repair bulletins for Jeep Grand Cherokee point to the following failure distribution:

55%
Burnt-out heating element inside the Bank 2 Sensor 1 O2 sensor (Jeep OEM Part)
25%
Blown O2 heater fuse in under-hood fuse block (Jeep OEM Part)
12%
Corroded or broken heater power/ground wiring (Jeep OEM Part)
8%
Faulty heater driver circuit in the PCM (Jeep OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for Jeep Grand Cherokee.

3. Step-by-Step DIY Repair Guide for Jeep Grand Cherokee

01
Check O2 Heater Fuse

Inspect the O2 HTR fuse in the engine fuse box with a test light or multimeter. on the Jeep Grand Cherokee equipped with 3.6L Pentastar V6 (293HP) / 5.7L HEMI V8 / 4xe PHEV (375HP).

Required Tool: Fuse Puller, Test Light
02
Test Heater Resistance on Bank 2 Sensor 1

Unplug the sensor connector and measure resistance between the two heater pins. An open circuit (infinite ohms / OL) confirms a dead internal heater. on the Jeep Grand Cherokee equipped with 3.6L Pentastar V6 (293HP) / 5.7L HEMI V8 / 4xe PHEV (375HP).

Required Tool: Digital Multimeter
03
Replace Bank 2 Upstream O2 Sensor

Remove faulty sensor and install a new OEM oxygen sensor with built-in heater. on the Jeep Grand Cherokee equipped with 3.6L Pentastar V6 (293HP) / 5.7L HEMI V8 / 4xe PHEV (375HP).

Required Tool: 22mm O2 Sensor Socket, Ratchet
04
Clear Codes and Perform Cold Start Verification

Clear DTCs and allow engine to cool down, then restart to confirm P0155 does not return. on the Jeep Grand Cherokee equipped with 3.6L Pentastar V6 (293HP) / 5.7L HEMI V8 / 4xe PHEV (375HP).

Required Tool: OBD-II Scanner
Recommended Parts & Testing Tools

Equipment for Diagnosing Jeep Grand Cherokee (P0155)

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Direct-Fit Replacement Part

Jeep Grand Cherokee OEM Replacement Sensor

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Direct-fit replacement assembly engineered to OEM tolerances for Jeep Grand Cherokee.

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Sensor Signal Voltage Meter

AstroAI Auto-Ranging Digital Multimeter

4.6 / 5.0 (Best Seller)

Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.

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Top Mobile OBD-II Scanner

BlueDriver Bluetooth Pro OBDII Scan Tool

4.7 / 5.0 (50,000+ Reviews)

Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.

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Other Common Fault Codes on Jeep Grand Cherokee

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Jeep Grand Cherokee:

4. Jeep Grand Cherokee P0155 FAQs

What causes code P0155 to trigger on a Jeep Grand Cherokee?

On the Jeep Grand Cherokee (3.6L Pentastar V6 (293HP) / 5.7L HEMI V8 / 4xe PHEV (375HP)), P0155 is most frequently caused by Burnt-out heating element inside the Bank 2 Sensor 1 O2 sensor or Blown O2 heater fuse in under-hood fuse block.

Where is the OBD-II port located on my Jeep Grand Cherokee?

On the Jeep Grand Cherokee, the 16-pin DLC diagnostic connector is located Under driver side dashboard above foot pedals. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.

Can I safely drive my Jeep Grand Cherokee with code P0155?

Yes. The sensor will take longer to warm up, causing brief open-loop fuel delay on cold starts. Given that P0155 carries a Medium severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.