P0E7C: Coolant Bypass Valve B Control Circuit Low

P0E7C says that the wiring which operates bypass valve B reads too low, typically because a wire or the actuator itself has a ground fault. Stellantis documents the code: bulletin 18-071-26 (revisions A and B, October 2026) for 2025 RAM 1500 pickups fitted with the Hurricane straight-six, SO or HO twin-turbo and bulletin 18-082-26 for the 2025 Wagoneer and Grand Wagoneer name it among the faults cured by new engine control software, with the check engine light on. That points to calibration as a frequent trigger on these engines, besides real wiring damage. A low reading on the line keeps the valve from being driven as intended, so the coolant split between loops is no longer under control. CARB lists such outputs among the components that need circuit monitoring. High and open faults are P0E7D and P0E7B.

Symptoms

• Check engine light
• Often no noticeable driving symptom

Most likely causes

• Engine control software needing the update from the manufacturer bulletin (Stellantis 3.0 Hurricane)
• Valve B control wire shorted to ground
• Internal short in the valve B actuator

What to check, in order

Start with the simplest. You can tick off each step.

1. With the engine cold, check the coolant level; never do this when the system is hot
2. With the connector unplugged, check whether the signal wire is making contact with ground.
3. Check the actual temperature in live data
4. Make sure the fan comes on when it should
5. Check the thermostat and connector
6. Measure the sensor and replace it if its readings do not make sense

Good to know

• Repair difficulty: medium
• It affects emissions.

What each character of P0E7C means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• E: Subsystem depends on the code range
• 7C: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0E7C?

Watch the temperature gauge. If it climbs or a warning appears, stop the car in a safe place and turn off the engine: overheating can cause serious damage.

What causes code P0E7C?

The most common causes are: engine control software needing the update from the manufacturer bulletin (Stellantis 3.0 Hurricane); valve B control wire shorted to ground; internal short in the valve B actuator.

Related codes

• P0E7BCoolant Bypass Valve B Control Circuit/Open
• P0E7DCoolant Bypass Valve B Control Circuit High
• P0E7ECoolant Bypass Valve B Control Circuit Range/Performance
• P0E76Coolant Bypass Valve A Control Circuit Low
• U063CLost Communication With Coolant Bypass Valve Actuator B

Sources

• static.nhtsa.gov: MC 11038497 0001
• static.nhtsa.gov: MC 11038502 0001
• law.cornell.edu: 13 CCR 1968.2

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.