P042E on RAM
Exhaust Gas Recirculation "A" Control Stuck Open
P042E on RAM vehicles indicates exhaust gas recirculation "a" control stuck open. Au7o has documented this code across 1 RAM model — most commonly on 2500. P042E is a generic (SAE-standard) OBD-II powertrain code set when the powertrain control module determines the EGR "A" control valve is stuck in the open position — commanded flow does not drop to the expected level when the PCM commands the valve closed. With EGR flowing when it shouldn't, exhaust gas dilutes the intake charge at idle and low load. Drivers typically see a check engine light plus rough or unstable idle, hesitation, stalling on deceleration, and a failed emissions test. Typical repair costs on RAM range from $500 to $1,800, depending on the specific model and root cause.
Common Causes of P042E
- •EGR valve carboned up or stuck open by soot deposits
- •Failed EGR valve or its internal position sensor
- •Clogged or partially blocked EGR passages and cooler
- •Wiring, connector, or ground fault in the EGR valve control circuit
- •Vacuum leak or stuck vacuum solenoid on vacuum-actuated EGR systems
- •PCM software/calibration issue or, rarely, a failed PCM driver
P042E on RAM by Model
RAM 2500(1 issue)
- 6.7L Cummins EGR Cooler Clogging and Cracking2007-2024
The EGR cooler routes hot exhaust through a coolant-jacketed heat exchanger before recirculating it into the intake. Heavy soot loading progressively plugs the cooler and EGR valve, first showing as slight off-idle hesitation and rising EGTs, then triggering EGR flow/performance codes and limp mode. Worse, a clogged, thermally stressed cooler can crack internally and leak coolant into the exhaust/intake stream, causing white smoke, coolant loss, and potential hydrolock or catastrophic engine damage. Cummins service intervals call for cleaning the EGR valve/cooler roughly every 67,500 miles (2007.5-2018) or 75,000 miles (2019+), which many owners never perform.
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View P042E across all makes →Frequently Asked Questions
What does P042E mean on RAM?▼
P042E stands for "Exhaust Gas Recirculation "A" Control Stuck Open." P042E is a generic (SAE-standard) OBD-II powertrain code set when the powertrain control module determines the EGR "A" control valve is stuck in the open position — commanded flow does not drop to the expected level when the PCM commands the valve closed. With EGR flowing when it shouldn't, exhaust gas dilutes the intake charge at idle and low load. Drivers typically see a check engine light plus rough or unstable idle, hesitation, stalling on deceleration, and a failed emissions test. On RAM specifically, this code is documented across 1 model.
What causes P042E on RAM vehicles?▼
Common causes on RAM: EGR valve carboned up or stuck open by soot deposits, Failed EGR valve or its internal position sensor, Clogged or partially blocked EGR passages and cooler, Wiring, connector, or ground fault in the EGR valve control circuit, Vacuum leak or stuck vacuum solenoid on vacuum-actuated EGR systems. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P042E on a RAM?▼
Repair costs on RAM range from $500 to $1,800, depending on the specific model and root cause.
Which RAM models have P042E documented?▼
Au7o has documented P042E on 1 RAM model: 2500.