Trouble codes › By vehicle › Jeep Grand Cherokee
Common check-engine codes on the Jeep Grand Cherokee
2005-2021
Grand Cherokees with the 3.6L Pentastar V6 (2011 on) and the 5.7L Hemi V8 share Ram's well-known problems: oil filter housing leaks on the 3.6L, Hemi lifter wear, EVAP leaks and electrical module codes.
Most common: P0520, P0300, P0456, P0420, P0562, P0128.
Known problems on the Jeep Grand Cherokee
- Chrysler 3.6L Pentastar oil filter housing leak and oil pressure sensor (P0520, P0521)
- 5.7L Hemi lifter and camshaft wear ("Hemi tick") (P0300, P0301, P0302, P0303)
P0520 Engine Oil Pressure Sensor/Switch "A" Circuit
P0520 means the engine computer isn't getting a usable signal from the oil pressure sensor; check the oil level before assuming it's just the sensor.
On the Jeep Grand Cherokee: On the 3.6L Pentastar, the plastic oil filter housing in the engine valley is a well-known leak point, and the oil pressure sensor in it often fails with it. Replace both together. Chrysler issued a revised sensor for some 2013-2014 models.
P0520: causes, can I keep driving, and what to check first →
P0300 Random/Multiple Cylinder Misfire Detected
P0300 means the engine is misfiring in more than one cylinder, often from worn plugs or coils, a vacuum leak or low fuel pressure.
On the Jeep Grand Cherokee: On the 5.7L Hemi, misfire with a tick points to lifter or camshaft wear. On the 3.6L, early engines (2011-2013) had known cylinder head valve problems on some cylinders; check for bulletins.
P0300: causes, can I keep driving, and what to check first →
P0456 Evaporative Emission System Leak Detected (Very Small Leak)
P0456 means the EVAP system has a very small leak, often a gas cap that isn't sealing perfectly.
On the Jeep Grand Cherokee: EVAP very small leaks are common: gas cap, then the EVAP hoses and leak detection parts near the tank.
P0456: causes, can I keep driving, and what to check first →
P0420 Catalyst System Efficiency Below Threshold (Bank 1)
P0420 means the catalytic converter on bank 1 isn't cleaning the exhaust well enough, usually a worn converter, an exhaust leak or a lazy oxygen sensor.
On the Jeep Grand Cherokee: Catalyst efficiency, often with P0430: check for exhaust manifold leaks and misfires first.
P0420: causes, can I keep driving, and what to check first →
P0562 System Voltage Low
P0562 means the electrical system voltage is too low, usually a failing alternator, weak battery or bad connection.
On the Jeep Grand Cherokee: Low system voltage: weak batteries and charging problems on these Jeeps can set many module and network codes at once; test the battery and alternator first.
P0562: causes, can I keep driving, and what to check first →
P0128 Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
P0128 means the engine isn't reaching normal operating temperature, almost always a thermostat stuck open.
On the Jeep Grand Cherokee: Thermostat stuck open: common, and on the 3.6L the thermostat housing is plastic and can leak.
P0128: causes, can I keep driving, and what to check first →
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Common codes and known problems as widely reported for these model years; your vehicle may differ. Check nhtsa.gov/recalls and ask a dealer about service bulletins for your VIN, and confirm in your service information.