K40 relay symptoms my wife found the key that worked the doors and locks today. Any feedback is Jul 3, 2021 · Don't mess about with K40, unless you like the fact that you will be very likely re visiting the K40 over and over Don't faff about, your car is 18 years old, so is your K40, it's kinda an important part, just buy a brand new one from MB Dealer Parts, not chinese or used fleabay junk, MB Parts !! Aug 7, 2017 · cant it be a k40 voltage problem ? i suppose i have to check the voltage of the relay before changing my esp ecu I had terrible experiences with my MB dealer in regards to them diagnosing issues. Customer: Hi there I am in desperate need of some advice. Been to Mercedes 'experts', but can't find the problem. Still no crank with same symptoms. There are 5 separate relays soldered to this board. I replaced the whole module, but it was probably a failure of the relay controlling the fuel pump (2nd from left when viewed from the side with the fuses). ) I turned key and no check engine light. My old K40 still looked like brand new when I took it out. The K40 can give trouble either hot or cold. I've checked the battery & connections. If you can do some voltage checks when the lights are not working we can pinpoint the failure. Jun 20, 2011 · I went to walmart bought a code reader soldering gun and wire. Finally had the time to hookup and read the codes. The other 4 fuses do have power. Feb 24, 2019 · The ECU provides ground for the FP relay coil and this is the normal way the FP is controlled. They do not have any voltage going to them. The CPS won't cause a rough idle but it usually only acts up when the car is hot. Found the issue to be in the k40 relay. Hard to say based on the color of the CB at those locations. Customer: On the K40 relay SLK 230 connector e-pen 3 is supposed to receive a it is not getting that signal I can jump over a ground to it and the fuel pump comes on ground signal from somewhere it is not getting it is not getting Apr 6, 2023 · The K40 relay is a multiple relay unit and each fuse is in-line serving each individual power supply line switched by each of the internal 5/6 relays (number of fuses varies by engine and systems installed). Oct 10, 2012 · The fault was the K40 relay module, as suspected. S. The K40 is the one component who's failure can stop a R170 dead. used a different key to start car. Dec 11, 2021 · I had the no crank, engine fan running at full speed and yellow trangle symptoms. The usual K40 failure involves losing the supply, not the ground. It pays to carry a spare and be familiar with the K40 failure symptoms of no ECM communication, high speed cooling fan with key in position #2 and no power to the 15 amp fuses. I have a UK RHD R170 SLK 230 with all the symptoms of a K40 relay fault engine cut out, LIM light on, fast engine fan but no engine crank. Electrical problems are greatly affected by heat and humidity. Customer: I have a 2001 E320 4Matic Wagon. Fuse number F2 and F3 on K40 relay are getting no power but are not blown. 75 through the MBZ dealer (my cost) and used ones can be obtained from wrecking yards for around $35. Fast engine fan but no engine crank. A good electrician may be able to open the relay and locate a bad solder joint or a flaw in the circuit board but the problem is not always obvious. if you have some jump leads you could try connecting 1 lead between the engine and the other end on an earthing point on the body, just to test that theory Jun 20, 2011 · [EDIT - Myk] also see attachments in post 319 courtesy of @BaD_81 & @M4rCu5 Early SLKs suffered from soldered joint failures on the K40 pcb. During some of my reading, it said to test the fuses on the K40 relay for voltage. Jan 7, 2024 · Many first generation R170 SLKs eventually have issues starting up due to a faulty relay. Turn it off and it will go back to not starting. soldered a few connections and Diagnostics: I have replaced the K40 Relay, still will not start. Then it almost always cuts out and will not start again for possibly 2 or 3 hours. Nov 5, 2023 · The symptoms pointed to a faulty K40 relay that is known to give up. I used to have a CLK500 that got some pretty major water damage from a clogged drain vent. The K40 relay does not affect the brake lights. Please could anyone advise which connector powers the fuses F2 and F3 on the K40 relay? Any help is greatly appreciated thanks. Your symptoms are different from typical K40 symptoms, but I'd go ahead and replace it. Dec 5, 2013 · and if so what were the symptoms ?? Thanks . 2003 SLK32 AMG The facelift K40 Relay module looks more difficult to take Jul 13, 2012 · my V reg 230 slk runs fine in every way, until it rains. Then, the dash lights go out and everything is back to normal. sinbad · *Registered. My SLK died while driving home on the freeway. I would at least scout around for a replacement K40 relay while you perform these other checks. Apr 3, 2020 · As for the K40, if it IS the K40, you may be able to salvage it by re-flowing the solder at those 3 joints. Customer: Hi I have a 2000 slk 230 I have a fuel problem and have tracked it down to the k40 relay. Hit and miss on the reflow of these K40 issues. The K40 relay module only cost me $141. If I was to take an educated guess as to the problem I would say that the K55 relay is bad. The symptoms pointed to a faulty Substituting a known good relay is the best way to test this. Jan 29, 2023 · Are your symptoms cranking without starting? The K40 does not interface with the keyfob- it's more like a giant, sophisticated fuse. The dash lights come on and when I press the throttle, the engine does not respond although it is still running. I have just repaired mine. 3rd and 4th relay work but not sure what they do and the 5th works Sep 6, 2022 · Also I tried removing the K40 relay circuit board and re-soldering the 3 solder joints on the circuit board that some videos say are the real problem with the relay. the relay clicking noise you refer to would certainly point me in the direction of an earth fault or a starter issue. I have changed to a brand new K40. I do not have the dashboard message "no Start" either. I took the K40 out and it had the same PCB issue as the one in your picture …solder joints on top LHS were burnt and the PCB discoloured. May 14, 2010 · That doesn't mean it's the only cause. took the k40 relay out did a terrible job resodering it. I have a 2003 SLK320 I recently disconnected the battery to take out the K40 relay board & re-solder the 3 suspect connections in the left hand corner that give a lot of issues I did not have any symptoms but have read a lot about all sorts of issues that can happen & wanted to avoid them before they might have started. 00 or so. If my interpretation is correct, the no cranking symptom is a consequence of the failure of the K40 module to supply power to the fuel pump. And check the fan! Jan 9, 2020 · New here, my first post and my first 2001 slk 320. However, I'm assuming you mean the Engine Control Relay on the K40 board. May 15, 2010 · New Members - Update profile/post introduction - then avatar and posts/threads approved. It has been running just fine, and I needed to jump my 99 Volvo. (the key i had been using would not lock the door nor set the alram. May 17, 2006 · K40 relay or K40 relay module? Just searched the net for a k40 relay for my 98 slk230. I reinstalled it and still nothing but that does not mean that the relay is not still burned out. Looking at other post I started checking and cleaning fuses and ground wires and wiring for signs of damage. If I disconnect the battery for 10-15 minutes the car will start ONE TIME. I have taken it off and checked the relays and they all work except 2 Standing at the front of the car the 1st relay does not work nor the 2nd but if I push the contact over on the 2nd the fuel pump powers and the engine starts. Jan 14, 2016 · i was referring to the headlights being switched on, not the dash/interior lights. Any ideas what I can try next before passing it on to the garage to fix (I don't have a code reader so any tips to try would be really appreciated). After reading this and other forums I purchased a new K40 relay. Got the car and after 50miles, check engine light came on. I started the E320 and correctly jump-started the Volvo -- my wife was in the E320 and she said that a whole bunch of lights came on -- including the ABS and the ESP messages. K40 Relay - Right hand drive LHD opposite Remove neg batt term Remove Nov 3, 2006 · My 1998 slk230 just started symptoms of k40 relay issues. Thank you. When it will not start the fuel pump doesn't prime. This mainly affects smooth op and fuel pump. This issue is more common in the early model years from 1998 to 1999. Sep 4, 2022 · Hello everyone. After reconnecting the battery, when I turn the key I can hear the fuel pump prime. Apr 22, 2017 · Hi, I have an SLK 230 R170 with possible symptoms of a K40 relay fault. You say when you manually operate the ECR all is well, but the ECR isn't energising because it's not getting any supply. The OVP relay or K40 relay is located inside the black plastic box containing the ECU, in the passenger side engine compartment for left . When the K40 relay fails, the starter won’t even crank even if the battery is fully charged. P0410, p0170, p0173, p0410, p0130, p0150, p0155 and p0135. The facelifted models from 2000 onwards have less issues with the K40 relay. the pulse module starter lock out relay a possibility, no power to solenoid no signal i get signal on pink and red wire and violet but not on violet and white wire, i suspect the module but i by pass module car cranks but does not start when i test for ground on pink red with test light engine cranks but does not start. You can repair a K40 - they generally fail due to dry solder joints and there are posts on this repair procedure on this and other forums. Save Share Like. The following film describes some o E420 just cut off in mid drive and refused to start. I found what appears to be a k40 relay, but not the k40 relay module described in previous posts. Could the problem be in in the K40 circuit board between the connector block and the relay? Jan 7, 2022 · Replaced the K40 as the symptoms indicated this may be the problem, still no ignition/turnover, lots of warning lights, fan going. Both part suppliers said it is located "right front under hood", but I don't see anything that looks like the picture on their site. reinstalled k40. vxhtu dvsav jflokn vxtd eae ndcjhx eiugo kuavo omsged tqvy grspv nqcd hxu pmdhf wziiq