As if the fuse were a light bulb, the interior of the fuse will be black and unattachable if the power lines within the fuse have been burned apart and no longer connect. Many a good tech has been caught out by jumping the gun and calling a perfectly good controller faulty, only to find the problem is still present with a shiny new spendy one installed. TRY THIS! OBDII reader won't communicate with PCM | The Diesel Stop Finally, the DLC or data link connector will be connected and other procedures will be taken to fix the non-communication issue. There are a number of reasons why the DLC can fail, including as being damaged or burned, being used to charge a gadget, or being plugged in. There could be various possibilities that make your OBD2 port not work properly but the problems are typically related to the OBD2 fuse, aftermarket system. Fuse 12 is the obd connection it's one of two 7.5 fuses in the top section. Assuming that the DLC and the fuse are functioning properly and your OBD2 is still not communicating, this is the most likely culprit. OBD2 Has Power but Wont Connect: What to Do? Cant connect to the ecm but the OBD2 port has power. OBD2 does not communicate - Car Talk Community This terminal should be powered at ALL times. Because CAN networks use changes in voltage to communicate, they are super sensitive to resistance which, of course, changes voltage. In short, if both the DLC and the fuse have no problems, this one is likely the reason why your OBD2 wont communicate. Floor Jack VS Scissor Jack? I suggest you check fuse 29 very carefully. How do I troubleshoot this problem? Namely the Corolla and a 2011 5th gen HiAce. read more Greg Shop owner, technician Vocational, Technical or Tra. The most common cause of being unable to connect to the car is an issue with the ECU, either an internal fault or a wiring issue. Scan tool (3 2007 Chevy 4500. Once you find the port hook up the connector and connect the other end to .. But if it has power but refuses to connect, you may want to examine its connection to the rest of your system. Get it replaced so that you can detect the error codes and allow them to be displayed. OBD ELM327 pairs but won't connect may because of your wrong operation, so i suggest you ask the OBD ELM327 technicial support . Do not connect to the body or chassis ground but to the battery terminal directly. In addition, well check the resistance of the CAN network. OBD II won't communicate - Ford F150 Forum David test most of the tools before writing a review. You should see +12V between pin 16 (+12V) and pin 4 (Chassis GND). Many controllers that are fitted under the hood are pretty durable and can withstand moisture, but controllers fitted inside the cabin arent built to withstand moisture since they arent expected to get wet. Now, measuring resistance not at the DLC but instead at CAN In and CAN Out (at the disconnected controllers block connector) will identify which side of the circuit is at issue. Cig lighter works but obd2 still doesnt. Have no power at pin 16 of obd2 port. I have 2 OBD scanners, a handheld one and a generic ELM327 bluetooth dongle. Thus, if it starts to communicate, you can start testing out your cigarette lighter. A strong battery is critical. All by the way for a fraction of the cost of a new main dealer fitted unit.