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Vehicle is an Isuzu ELF, NKR85 model, 4JJ1 engine.
Anyone know what the differential pressure specs/lower limit/upper limit should be for a DPF?
We've used the scan tool to run the regeneration process twice. First time was a slow 2 hour forced regen. Second time was a forced 20 minute regen.
Ran live data right after the first regen & differential pressure was at 0.72kPA (idle). Pressure reading of 0.63kPA (idle) after second regen.
Cleared fault code P242F (DPF overaccumulation) but it came back on during test drive.
We removed the differential pressure sensor for testing.
Using multimeter:
- 5V reference is available
- Ground terminal is good
- Signal terminal is good (0.03V unplugged, pull down circuit?)
Using scan tool data:
Attached vacuum/pressure pump to one of the sensor inlet ports & left the other side open to atmosphere.
Sensor reads 0kPA with no vacuum/pressure applied.
Pull vacuum & the sensor reads -kPA (reading decreases proportionally as more vacuum is applied).
Apply pressure & the sensor reads +kPA (reading increases proportionally as more pressure is applied).
Reset DPF memory & cleared fault code. Left the vehicle standing for a couple of hours. KOEO, differential pressure @ 0.0kPA. Started it up again, differential pressure now at 1.6kPA. This increases up to 15.6kPA when engine is revved up to 2800-3000rpm, during which check engine & DPF warning lights did not come back on. 5 minutes in to engine start up and DPF light back on at approx. 8kPA.
Unlike most vehicles that have a P242F code, this vehicle has good power when driving. Driveability is therefore not an issue. The check engine & DPF warning lights are however an issue.
