D-Max & Mux DPF Faults? It Might Be the Valve Clearances
By Clinton Brett
The Isuzu D-Max and Mux are now one of Australia’s most popular cars and popular for DPF/DPD faults. Last year Isuzu eventually got to the bottom of the major cause of the DPF differential pressure sensor failure. The wrong material was used on the hoses which feed the exhaust pressure to the sensor. The hoses were not adequate to cope with the heat, causing the glycerin to seep from the rubber into the highly sensitive pressure sensor, resulting in complete failure of the sensor.
This makes sense to me (pardon the pun) as I had been driving around for 12 months in my own car (Musso UTE) with test hoses connected for the DPF diagnostics training courses and my DPF
sensor failed. My rubber hoses were standard fuel grade hose, not suitable for high exhaust temperatures. That’s a bonus tip to what I am about to share with you. Valve clearance is the greatest overlooked contributor to DPF related faults and symptoms. Don’t base your customers’ additional service procedures on what the manufacturer recommends. They do not know what each
customer does with their vehicles but as a regular independent or OEM dealership workshop service provider, you need to be aware that some driving conditions will contribute to premature
failures.
Simply because the vehicle is not meeting the appropriate diesel engine conditions- Constant haulage of heavy loads, minimal idle periods and less stop start cold operation. The following symptoms can be evident when valve clearance proves to be the cause of the listed fault codes below- Excessive crankcase ventilation, excessive smoke, poor fuel economy, running rough, misfire. Engine light on, engine derated and DPF/DPD fault codes present may include:
