a 2008 annual car FAW Mazda 6, 2.3 L engine mounted, 5-speed manual matching / transmission from one, mileage of 24,000 km, the user reflect the car dashboard indicator suddenly during deceleration of all lights, turn off the vehicle, the engine is restarted, no response. Then I got the car towed.
FIG 1
After receiving the car, the test was found, regardless of the vehicle shift lever in N or P range block, no starting the engine reaction. After the ignition switch is opened, charging indicator on the dashboard warning light and an engine oil pressure warning light were the normal lighting, the automatic transmission gear display correctly. I first measured battery voltage, the battery voltage is normal, check the battery pole terminal is completely normal. It would not be a problem with the starter line? After inspection, the starter wiring and fuse (FIG. 1) were normal. According to the test results, the author determines the possible causes include damage to the starter, the starter relay and associated damage to the harness and the transmission gear switch is damaged.
FIG. 2
decided to first check the starter relay and associated wiring harness. According to the circuit diagram (FIG. 2), the relay coil resistance measured I 98 Omega ;, normal measurement result; measuring relays the power supply, B / Y line voltage 12 V, with the ignition switch is opened, the voltage B / L line 12 V, with normal detection result; harness between the measuring relays W / L of PCM lines to 4I normal foot, after the ignition switch is opened, measure the line voltage 12 V, with normal test results. By checking the above, the starter relay may determine its associated line is normal, the switch gear also normal. There may be problems on the PCM control section or the starter. Then I check the starter. Disconnect the starter relay shorting B / Y and R / Y terminals, the starter is operating normally, but did not start successfully (ignition switch is turned on). Through the inspection, proof of normal starter, but PCM has no control starter operation. By testing the operation of the starter, but the engine is not the car phenomenon analysis, PCM may be damaged.
Figure 3
Is connected to the engine control system fault diagnostic testing, fault diagnostic display device but unable to communicate with PCM. Due to a failure diagnostic apparatus can not communicate with the PCM, PCM description of operating voltage or no damage. I decided to check the power supply and Ground PCM is normal. The circuit diagram can be seen, there are two PCM car power supply, i.e., by the regular power source and an ignition switch controlled power supply. After examination, the control of the ignition switch 15A fuse (FIG. 3) blown. I use the multimeter to measure resistance of the fuse is to be described later 0.5 Omega ;, fuse circuit and a short circuit member. For this reason, we decided to further examine the relevant line.
Figure 4
Now that a circuit diagram, while the fuse is to provide power to the ignition coil and the PCM. In view of the smaller chance of damage to the PCM, PCM I visual inspection No damage associated wiring harness short circuit, so that the initial determination of the ignition coil (FIG. 4) or presence of short-circuit point associated wiring. By visual inspection found no ignition coil related wiring harness damage occurred. This is independent of the vehicle engine with an ignition system, each cylinder each have an independent ignition coils. Sequentially disconnect plug ignition coil, measured with a multimeter at a 15 A fuse, no short circuit, faulty ignition coil proof. But what exactly is the ignition coil cylinder fails it? If the face of the ignition coil connection terminal, from left to right pins A, B and C. A PCM terminal pin connector, B Ground terminal feet, C is the foot end of the ignition switch controlled power supply. Was measured, the resistance value of 0 in the second cylinder of the engine ignition coil B-C, indicating that has been damaged.
Since the short circuit between the second cylinder of the engine ignition coil B-C, leading to the ignition coil is supplying 15A fuse burned. Since the fuse and power while the PCM is, when the ignition switch is opened to start the engine, because the fuse is blown, it can not provide power leads to PCM, causing it does not work, so that the PCM can not properly control the operation of the starter.
After the replacement of the second cylinder and replace the ignition coil 15 A fuse, smooth start of the engine test, troubleshooting.
(first Du Village)