Temporary loss of power steering assist

I have a 2003 Honda Civic, 140,000 miles. I have been experiencing a temporary loss of power steering when slowing down (I usually notice it while applying the brakes and making a turn). When I let off the brakes, the power steering usually comes right back on. This does not happen all the time, maybe once or twice a week. I brought the car to my mechanic and explained the problem. They asked if it happened in wet weather… we have had a lot of wet weather lately, but it has happened on very dry days too. They checked it out and couldn’t find any problems or reproduce the effect. The problem has come up a few times since then. Any ideas about what’s going on? Are there any possible problems that could have been overlooked by my mechanic’s inspection?

The reason they asked about wet weather was to determine if the belt to the power steering pump was slipping. If the pump stops spinning, then the power assist to the steering is lost. Have you ever replaced the accessory belts and the timing belt? If you haven’t done the timing belt yet, your overdue. And this is an interference engine, meaning a snapped timing belt could ruin the engine. Consider this and get the accessory belts replaced with the timing belt. On this engine (1.7L 4-cyl), the water pump should also be replaced with the timing belt.

The engine rpm may be dropping too low to drive the power steering pump fast enough. This could be because the engine is out of tune, or the power steering pressure switch isn’t working, or etc.
Drive in large circles (in a large parking lot, cul de sac, etc.). Pay attention to the engine rpm (you could have a passenger do the observing). Does the rpm drop below the usual idle rpm? [You can tell by SOUND, if you don’t have an rpm gauge.]

Good advice but I think you should replace the drive belt. Make sure to pay close attention to the timing belt advice because this is a critical area. Sometimes you can open the hood and watch the power steering pully (mark it with chalk or white paint) as someone slowly turns the steering wheel. The belt can slip right over the pulley without turning it. Mist the belt with water and I bet the pulley won’t turn. The belt may be loose too but I would replace it anyway.

Thank you for the quick replies. I’m going to try and check out some of these suggestions later with a friend that’s a little more comfortable under the hood than myself. I didn’t realize how the timing belt could affect the power steering at low RPMs. I should definitely have that looked at, I have a sinking feeling that is closer to the heart of the matter.

I think you are misunderstanding the posts. The “drive” belt for the vehicle can slip and cause loss of power steering. The “timing” belt drives the camshaft by way of the crankshaft and does not drive the power steering pump. The only reason replacement of the timing belt was mentioned is because your engine is an “interference” engine. If you have 140K on the engine without replacement of the timing belt then your engine could be destroyed if it breaks. It’s overdue if it has not been done already.

Yes, I may have misunderstood something. I do realize the difference between the drive belt and the timing belt, but I may have misused referencing the timing belt. My power steering pump and drive belt were replaced at 90k miles. I know that the drive belt can slip when wet and cause a loss of power steering, but the loss of power seems to happen whether it is wet or dry. Since I had the pump, drive belt and steering fluid checked out a few weeks ago, I thought the problem may be what hellokit said: “The engine rpm may be dropping too low to drive the power steering pump fast enough.” I (maybe mistakenly) assumed the timing belt had something to do with that. I’m pretty sure that it had been replaced as well, but I can’t be positive - so regardless of whether the timing belt can affect the power steering, I found it to be good advice to have it checked/changed anyway.

I watched the RPM today when slowing down to under 5mph and turning, but did not notice it going particularly low (at least not lower than when idling). And I can’t seem to reproduce the steering problem intentionally - it just happens once or twice a week (while the brakes are applied and at around 5mph). Please excuse my ignorance… I never had any problems with my car until about 120k miles. I just brought it in for regular service and oil changes and was satisfied. At 120k miles, I just figured that that car is getting old and things happen. Now that I found something unusual that my shop can’t solve I sought out a new venue for a solution, but I’m just now getting educated about what’s going on under my hood. Believe me, things will be different with my next car!

Drain the P.S. fluid with a turkey baster. Remove the plastic reservoir and clean out the filter screen you will find in the bottom of of it. Put everything back together and refill with fresh Honda-approved fluid… It might not help, but it can’t hurt…