Crew low heating output

I've seen similar issues on the Crew before. Given the symptoms, the water valve does sound like a strong contender. Before condemning the valve itself, though, have you performed a thorough inspection of the associated electrical connections? A defective cable or plug can indeed manifest in the symptoms you've described. Specifically, scrutinize the integrity of the wiring harness leading to the valve and ensure the connector is free from corrosion or damage. Measure the voltage and ground at the connector to confirm power delivery to the valve. Also, is the engine reaching normal operating temperature? A faulty thermostat could also contribute to reduced heating output.

Thanks for the detailed reply. When you say 'measure the voltage', what kind of voltage should I be seeing? And how would a faulty thermostat affect the error code?

Regarding voltage, you should consult the Nissan Crew's service manual for the precise voltage specification for the water valve connector under normal operating conditions. Typically, you'd expect to see battery voltage (around 12V-14V) when the valve is commanded to open. As for the thermostat, if it's stuck open, the engine will struggle to reach its optimal operating temperature. While this wouldn't directly trigger a water valve error code, it could indirectly impact the heating performance and potentially trigger other temperature-related faults. Given your intermediate experience, I suggest taking it to a trusted mechanic for a proper diagnostic assessment. They'll be able to perform a more comprehensive system check and pinpoint the root cause.

Appreciate the help. Took it to the shop, and it was indeed the water valve and a corroded connector. Cost me 95€ all in. All sorted now.