Engine light came on was told PO128 Coolant thermostat temp was below regulating temp. PO 342 Camshaft Position sensor A circuit low input Banks7 or single sensor and PO 420 Catalyst System Efficiency Below threshold Bank 1. What type of repairs could this be? Can it be driven some before repair?
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2005 Suzuki Reno Question: PO 420 Catalyst System efficiency Below threshold Bank 1
Answer #1ZeeTech January 13, 2011, 20:03Master
Looks like the car will need a new thermostat (not an expensive repair), a new Cam Position sensor, but first I'd get the circuits checked between the sensor and the ECM.
The other is the catalytic converter - this would be the most expensive item, but if you have less then 80,000 miles it might be warranted as a federal emission part.
If you still have the owners manual check the "Warranty" section. It could be actually 100K miles on the 2005 models.
I'd get the repair done ASAP, with the stuck open thermostat the ECM will stay in open loop mode (thinking the engine is cold) and keep damping fuel into the engine, so your gas mileage will be pretty bad, it could also be the reason for the damaged cat.converter - beside your heater won't work good either.