P26A3: Ram coolant-valve performance fault: ground test before contamination repair

The named cause is stop-leak contamination

P26A3 identifies engine coolant bypass valve A range/performance in this Ram bulletin. FCA describes contamination from stop-leak pellets causing valve failure. The resulting repair can involve cooling-system flushing and a new three-way valve, but the procedure first separates an electrical-ground problem from the contamination path. This makes a measured circuit check more useful than ordering a valve from the code description alone.

A failed ground test changes the repair

The technician checks for other LIN-bus faults and follows their diagnostics, then load-tests the valve’s Z908 ground circuit for excessive resistance. If the circuit fails, the instruction is to repair the ground and perform the powertrain verification test. Only a passing circuit test proceeds to the coolant-drain and flushing branch. Ask for that test result on the repair order; a simple statement that the connector was plugged in does not describe the specified loaded-circuit check.

Valve replacement alone can leave the cause behind

For the contamination branch, the source requires discarding the old coolant so impurities are not reintroduced. It describes separate flushing paths for auxiliary heat exchangers, radiator and engine, with pressure limited to 138 kPa, then valve replacement and fresh coolant. These workshop-specific paths should not be replaced with an unrestricted compressed-air blast or an added stop-leak product. After service, verify the original fault and cooling behavior. Repeated valve failure warrants checking whether contamination removal and the initial ground diagnosis were actually completed.

Source and applicability

FCA bulletin 07-007-24, August 2024: 2023–2024 Ram 1500 DS with 3.6 L ERB engine, built June 1, 2023–February 16, 2024.

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