Folks,
My 96 e300d (157k) acts up when the weather turns cold. Runs perfectly during summer . The temp fell to about 28f here in N.texas the last couple of days.

1. Last morning when i tried to start the car in the morning, it cranks but no start. The charge battery warning flashes followed by check engine electronics. The code i pulled was P120.

2. I kept cranking with the pedal pushed down and it finally started. Drives great no issues. If start i immediately after a drive it starts fine but after it is parked for couple of hours same problem again.

I checked the battery & alternator and all is good. So what does cold weather do to trigger the p120. BTW, it did the same thing last winter (2015) but luckily we didn't have much of a winter in N.Texas . So, any input on the root cause of this problem would be appreciated.

smk_texas

My list says P120 is a throttle position sensor error. You might check the connector to see if it's dirty or corroded; perhaps it's worse in cold weather. I suspect the IP doesn't deliver fuel if the throttle position sensor is misbehaving. Another possibility is a failure internal to that unit, which may require replacement; you don't want to know the price for something that is just a couple of ganged potentiometers.

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

The throttle position sensor error code can have a multiple causes. There are a number of sensors that work in combination with one another which can cause this code besides the "throttle position sensor" itself. which is located adjacent to the firewall, drivers side.

There is a small black sensor connected to the intake manifold atop the driver side wheel well.

There are two other sensors located on the side of the air intake filter box. Both of these sensors have the same part number. One controls the resonance flaps, and the other controls the EGR valve.

On the underside of the intake manifold, there are two vacuum devices that control the resonance flaps.

All these sensors are all connected by small rubber vacuum lines, that can spring a leak and cause a code, so I would check those out the vacuum lines themselves first.

The second thing I would do is disconnect all the electrical plugs to each sensor one at a time, and spray each one with electric contact cleaner, and re-attach. Good luck!!
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96 E300d