Mercedes-benz w203 voltage regulator replacement – (2001-2007) c230, c280, c350, c240, c320 pelican parts diy maintenance article electricity in india


The alternator charges the battery and provides your car with a constant source of electricity while the engine is running. The voltage regulator does just what it says: it regulates the voltage from the alternator. Your battery should read a little more than 12 volts with the engine off. Next check the voltage of your charging system under load, the voltage should be within 13.2: 14.5 volts d/c. To load, have engine running at idle, turn on headlights and HVAC blower motor. Never disconnect a battery cable while engine is running to test alternator, you may cause damage to alternator or other electrical components from the surge in amperage. If your battery appears to be leaking, then your voltage regulator has probably failed. The battery will usually only leak acid if it has been overcharged at a much higher voltage. If the voltage measured at the battery is more than 14.5 volts when the engine is running, then the voltage regulator is probably bad. If your battery has boiled over and has acid overflowing out the top, make sure that you clean up any spilled acid immediately. Dousing the area with a water and baking soda solution should help considerably to neutralize the acid, and prevent it from eating away at the metal.

A large amount of the time when there is an electrical problem with the charging system it is the voltage regulator yet people just swap out the entire alternator because it comes with a new voltage regulator included because it is easier, fixes the problem and most people do not understand how an electrical system works on their car. If your electrical issues are caused by a faulty voltage regulator you can save your self a lot of money by just replacing the defective part.

Comments: Hello, I have a 2003 e320, ive had an intermittent fault with the alarm going off. I sometimes have to drive it for a couple of miles before it stops or I can stop it with the key fob, it has been checked there is no sign of moisture and the siren was disconnected, but now the battery is at 95% but the voltage is too low to power stereo and sat nav etc. Will changing the battery sort this or should I change the voltage regulator anyway as its done 113k anx im told it may help?

Followup from the Pelican Staff: Yes, either the voltage regulator or the alternator. Most times the voltage regulator will do it. With your vehicle info handy, give The Pelican Parts parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.

its randomly keeps showing "esp not available check owners manual" i used a scanner tool and showed nothing. i took it a mechanic and used a more expensive tool to scan and it showed nothing. changed the battery yet still shows, the alternator voltage shows 13.76 under load and 13.81 no load. the weird thing is that it keeps doing that in cold weather and barley do that in a hot weather. i cleaned all of the ground connections to the body and every thing. im lost, any tips or any type of help? as an electrical engineer i failed to diagnose the problem XD

Comments: Hey I have a 2002 Mercedes C230. I was having the issue that my car would turn off when it stops sometimes or when I turn the key the engine sounds like it’s trying to turn but it won’t turn on. I took it to a Mr. transmission and they ran a test to get code P2600 87 Voltage circuit fault. No other electronic issues. Will replacing the voltage regulator do the trick? Thanks!

Comments: My car dies out about once or twice a day. I have a clk500 2003. My MAF is good and the vacuum hoses are all good also. MPG is excellent. Also when it dies, it doesn’t boggle down a split second and die out like it does when there is an air, fuel, or emission problem. It dies out instantly like someone flipped the ignition switch. And it starts back up no problem right away. On the dashboard it shows "visit workshop" and the battery symbol. Do you think the voltage regulator is going out, causing the engine to cut out to prevent damage to electronics?

Second question. My transmission is leaking a little after I changed my 13 pin connector. I think I didn’t tighten it enough. If I just remove the plug without removing th connector, do I still need to drain the atf or can I leave it in? Thanks in advance!

Followup from the Pelican Staff: 1: I would assume a circuit is opening or shorting. I would start by checking the DME for fault codes. If the system is not working properly, a fault code will be set. This will be your best bet when diagnosing.

Comments: I have a 2004 E270 with 83000 on clock. Since I’ve had it sometimes a message comes on dash saying Battery protection, convenience functions temp. unavailable….then usually went off after a mile or so. Now it seems to stay on for much longer & when been switched off for a short while will initially say that convenience functions available again but the go back to saying unavailable..yet nothing seems to "unavailable". Had new battery approx 2 years ago and been back to get it checked and its good 12.25V and also checked alternator which they said was OK but a bit sluggish.

Followup from the Pelican Staff: Could be that the alternator slow reaction is when you’re receiving the message? I would check the voltage when you’re getting the error message and see if it is indeed low. Should be 13.1 v or higher – Casey at Pelican Parts

Comments: I have a 2001 E320 my situation is that sometimes the volume of the radio goes completely out, when turn the air sometimes works full and sometimes only on the 2nd line, I keep getting false messages on info window. What kind of electrical problem can it be?

Followup from the Pelican Staff: Wow, sounds like you have multiple issues. Like any other problem you must use the information you have to diagnose the issues. For instance the radio, I would try to spray some contact cleaner in the volume knob area and see if you get any improvement, fiddle with the knob see if that helps. The fan issue is likely a resistor issue for the interior blower. We do not have an ar5ticle on that but I am sure a quick Google search will provide some results. – Casey at Pelican Parts

Comments: Hello.. I have a 2006 c230 mercedes , was driving when I suddenly received a message on the dash reading "check battery alternator see workshop soon". My radio then read low voltage and stopped working. Car shortly after stalled, and now it won’t start even after trying to jumpstart it. could this be VR, bad battery, or alternator?

Comments: This is a Google translation. I’ve changed the alternator and battery. The battery in the rest 13,4V. at start 12.5V. shortly after 18V. Idle 13.4V. 1500rpm 14.3V. After 3 … 4 minutes remain 18V at any second. Since there seems to come more. During all the time warned of the brake lights do not work. Both right and left. other codes: ESP, SRS, and BAS have occurred. some suggestions to the problem? it may be the alternator is wrong even if it is new?

I bought a 2004 C180 Kompressor, and ai test the charging. The results are those: When I start the engine, and it running idle 850-900 rpm I have 13.3V when I touch the cass pedal 1100-1200 rpm charging is 14.2V. If I drive the care about 20-30min, on load, charging is 13.7-13.8. On idle running is 13.3-13.4. It is normal or should I visit an electrician?