P0420 / P0430 Fix for Jeep Grand Cherokee

Whether you're running the 3.6 Pentastar V6 or the 5.7 HEMI V8, the Jeep Grand Cherokee is a frequent P0420 / P0430 offender, usually from aging factory cats or after an aftermarket exhaust. Before you drop serious money on new cats, this is the part to try first.

The Fix: 90° O2 Sensor Spacer

The Brockett Built 90° O2 sensor spacer threads into the downstream (rear) O2 bung and moves the sensor out of the direct exhaust stream, so the ECU stops flagging catalyst efficiency. CNC-machined for the M18x1.5 thread, a direct fit for Jeep downstream sensors.

• Both the 3.6 Pentastar and 5.7 HEMI are dual-bank, so you may need two spacers. P0420 only means one; P0420 plus P0430 means two. Grab the 2-Pack.
• About a 10-minute install per side. Clear codes and drive a readiness cycle.
• Downstream (rear) sensors only, never the upstream sensor.

Fitment

Jeep Grand Cherokee (WK / WK2, 2005+): 3.7 V6, 4.7 V8, 3.6 Pentastar V6, and 5.7 HEMI V8. All use the standard M18x1.5 downstream O2 thread.

FAQ

Will it affect performance or fuel economy?
No. The downstream sensor only monitors cat efficiency, it doesn't control fuel trim, so your tune and mileage are unaffected.

Legal note: designed for modified/off-road use. Check local emissions laws.

Get the 90° O2 Sensor Spacer: $42 single / $84 2-Pack →

Machined by Brockett Built in central Illinois. Ships same or next business day. 30-day fitment guarantee.