Which tire pressure rating should motorists heed?

Q: My mother has a 2011 Honda CRV with 13,000 miles and original tires. She just got back home after two months away and her tire warning light came on. The tire says 44 psi and the doorjamb sticker says 30 psi. I called the dealer and they said to go by the sticker psi. The tires look low at 30 psi. The Bridgestone tire manual which came with the vehicle says to use the doorjamb sticker's psi, as well. Why is there such a discrepancy between the recommended inflation level on the tire versus on the doorjamb sticker, and is it correct to use the doorjamb psi level? Again, the tires sure look low. Also, I set all tires at 30 psi and the dash light is still on. The dealer said it might take a little driving around for the light to go out unless it needs to be reset, which they would have to do at a cost. Could my car code analyzer (old cheap one) reset this light?

A: There is no discrepancy between the two different tire pressure specifications. Each is for a different purpose. The 44 psi shown on the tire sidewall is the pressure at which the tire will safely support its maximum load rating. This is not the carmaker's recommended operational tire pressure for that specific vehicle. The car maker's recommended tire pressure for optimum fuel mileage and tire wear is shown on the vehicle's doorjamb, in this case 30 psi.

Is there a question of safety with the two different pressures? No, the tire is absolutely safe at its 44 psi max inflation pressure, but the car will ride a bit firmly and the center of the tread will wear considerably faster.

The correct cold tire pressures for every vehicle are posted by the carmaker on a placard somewhere on the vehicle — driver's doorjamb, inside the fuel filler cap or on the inside of the glovebox door are common locations.

You didn't say whether both the tire pressure monitoring system light as well as the "Low tire pressure" warning symbol are on. If it is the TPMS light only, a modern scan tool may pinpoint a problem with the TPMS control module. If the "Low tire pressure" symbol is on, confirm proper tire pressures and drive the vehicle for several minutes at speeds above 28 mph to allow the pressure sensor to transmit its signal to the control module.

Q: My wife owns a 2004 Toyota SiennaE with 102,000 miles on it. Eight months ago she put on the parking brake and when she released it the parking brake light would not go off. And it's been on ever since then. The local Toyota dealer, a Honda and a local independent auto repair shop have not been able to fix it.

A: Hopefully one or more of the service agencies have eliminated the three likely causes for the parking brake light staying on as the vehicle is being driven — the pedal-applied parking brake mechanism has not fully released, stuck/binding parking brake cable or shoe or low fluid level in the brake master cylinder reservoir.

Two other possibilities — the brake warning light switch itself or a problem with the ABS. If the ECU detects a problem with the ABS it will illuminate the parking brake warning light. A scan tool might identify this type of problem.

Q: I just purchased a 2004 Acura TL with 93,000 miles on it. Beautiful car, but one problem is a very loud power steering pump when cold. Is this common and would a little Sea Foam help?

A: A few ounces of SeaFoam Trans-Tune will help clean and condition the power steering fluid — always good maintenance. My ALLDATA database pulled up Acura TSB 07-060 from 2009 that identifies this cold-start characteristic as being generated by aerated fluid caused by air getting past the inlet O-ring. A new O-ring might eliminate the noise.