Reading 9 different codes

ANSWER : Hello, and thank you for writing in. With a misfire detected on all cylinders, you need to direct your attention to a component that can cause the entire engine to struggle. Considering you have an EVAP code as well, and this is one of those components, you will want to focus on the EVAP system first. This may mean you have a vacuum leak, the canister needs to be replaced, or there is another similar issue. If the EVAP system checks out, turn your attention to the catalytic converters and your exhaust system. The p0731 code stands for an incorrect gear ratio, which means the transmission is slipping. Since this is the trickiest component to test or look into, you will want to focus in on this last. For more diagnostic help, contact our service department to schedule an appointment.

ANSWER : Hi there, the short answer to your question is no . A PCM with a P0601 (which is a memory module error in the PCM) cannot reliably retrieve codes for the codes you list (P0118 – coolant temp sensor, P0123 – throttle position sensor, P0193 – fuel rail pressure sensor.

Most likely, the P0601 prevents the PCM from getting any codes from the engine sensors. The memory module error may cause in data corruption for collected sensor values, lose of data over multiple sampling periods, or failure of the data collection to work at all. Replacing the PCM was a necessary expense.

If you need assistance with the "new" codes, I would recommend having a Check Engine Light inspection completed by a mobile, professional mechanic, such as one from YourMechanic, to diagnose the new error codes and get an accurate assessment of the repairs needed.

ANSWER : Hello. The MAP sensor reading on a scanner should read about 1.0 to 1.5 volts at idle and 4.5 to 4.8 volts at wide open throttle. The MAP should read 4.8 volts or more when you have the key on engine off. If either sensor is not within these specs, then replace have it replaced. Once you install the sensor, then clear the codes and road test the vehicle to see if code returns. If it returns, then you will need to have the entire pinpoint test done to check the wiring and ECM for problems.

ANSWER : Hi there. Those codes may or may not be related. Proper diagnostic processes will determine the root cause of the failures. When the ECM detects a fault it stores codes. It does not know why or what caused the fault, only that the fault is present. You can always try to clean the parts you mentioned, but it would literally be a blind guess and most likely not a proper repair. I suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts. Your Mechanic has several available technicians that can assist you with a check engine light inspection.

ANSWER : Hello and thank you for contacting YourMechanic. The problems that you are encountering with your vehicle, could be caused by the harness to the Throttle Position Sensor (TPS) or the computer itself.

Check the harness to the TPS for any debris or any corrosion. Hook up a paperclip to the harness and turn on the key. Use a multimeter and check for voltage at the pins of the harness. Make sure that the ground on the sensor is grounded and has no resistance. If you find that the harness is having too much resistance, then I recommend having the main engine harness replaced. If you have replaced the harness and still have the same problems, then the computer will need to be flashed or replaced.

I recommend having a professional, like one from YourMechanic, come to your home to diagnose your car’s no start condition before replacing any parts.

ANSWER : Once a trouble code is erased, it cannot be retrieved. The engine controller does not have a "recycle bin" like they have on Windows. If the car still has a problem, the code will come back up after some driving. However, the controller will not turn on the CEL until it has seen the malfunction on two separate "trips." A "trip" is a driving cycle where the car is started cold, driven until it is fully warm and through a certain number of accelerations, and shut down. So you might not see the CEL for a couple of days. As for the "head gasket sealer," I wouldn’t hold out too much hope of that solving a problem. At the very best it might put off the symptoms for a short while. If you need help interpreting codes that come up, or solving a head gasket issue, contact Your Mechanic. They can send a technician to your home or office to read the codes on your car and help you decide what to do.

ANSWER : When the check engine light comes on and you test it and get a code then you will need to have the pinpoint test done for that code until the problem is found or the problem cannot be verified again. Intermittent codes or problems are the most difficult to find since they cannot be verified in most cases. When you keep getting different codes then you may have connection issues. You should go through the wire connections of each of the affected modules that control the sensors giving codes.

ANSWER : Hi there. The oxygen sensor that trouble code P0157 refers to, is located in the rear of the exhaust and behind the catalytic converter. It’s main function is to regulate the amount of oxygen that comes from the catalytic converter. A lean mixture of oxygen and gas means that there is too much oxygen in the exhaust. A rich mixture of oxygen and gas means that there is not enough oxygen in the exhaust. This would cause a failed emissions test in most cases. However, there are multiple sources of this code beyond the sensor itself. In fact, most of the time, mechanics misdiagnose this code as simply the sensor – which appears so in this case. I would recommend reading this article so you can learn about the other causes of this problem.