P0AA1 - OBD Trouble Code

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The trouble code P0AA1 can be explained as Hybrid Battery Positive Contactor Circuit Stuck Closed. If the hybrid control module would detect a variation in the voltage coming from the circuit to the high voltage battery that is outside the parameters set by the automobile manufacturer, then it would store the P0AA1 error code. The hybrid control module might disable the high voltage system. This would also give rise to the illumination of the check engine light.

The engine control module, powertrain control module or the transmission control module monitors this circuit depending upon the particular automobile. The high-voltage power supply circuit is connected and disconnected by the system main relays as per the requests from the HV control ECU. There is a total of 3 relays (1 for the negative side and 2 for the positive side) for ensuring a reliable operation. The SMR1 and SMR3 should be turned ON initially for the connection. Then after that the SMR2 would be turned ON and SMR1 would be turned OFF. This process would protect the circuit from the high-voltage surge current by allowing the limit current to flow via the resistor. Then SMR2 and SMR3 should be turned OFF in the same order for disconnecting. It is the HV control ECU which would inspect if the relays have turned OFF properly. The proper functioning of the SMRs (CON1, CON2 and CON3) is monitored by the HV control ECU to inspect the faults.

What causes this problem with the Hybrid Battery Positive Contactor Circuit Stuck Closed?

• Some issues related to the system main relay
• Unlocked system main relay harness
• Unsatisfactory electrical connection in the system main relay circuit
• There can be inoperative HV control ECU

1. Hybrid Battery - A hybrid battery that has dead traction can be very problematic. It can result into a delayed or instant release of gases that are toxic or flammable. We recommend you to change it instantly without taking the risk of touching it as it may lead to a shock.
2. Engine Control Module - If there is any corrosion or breaks in the internal wiring of the harness, then it can cause a short in the ECM or can also cause corrosion in the ECM through the wiring harness. You can always rely on us as we have the best auto parts for our customers.
3. Inverter Cooler Pump - As part of the cooling system, the inverter coolant pump translates high-voltage direct current generated by hybrid batteries into alternating current for the motor to keep the system at the proper operating temperature. Thus, if the cooler pump if faulty, it should be replacing immediately.
4. Battery Temperature Sensor - A symptom commonly associated with a failing battery temperature sensor is an engine that surges during operation. The battery temperature sensor helps the system continuously adjusts the system voltage, and if it fails, this process may be disturbed. Thus, replace it now!
5. Powertrain Control Module - The onboard computer, or powertrain control module is the brain of the engine control system. Now if the brain is not working properly, then neither is the car engine. Get it replaced before the situation gets worse.
6. Electronic Control Unit - Is your car jump starting on reverse polarity? Or are you facing some intermittent starting issues? If yes, then it indicates that your electronic control unit is bad. So it is very important to replace the defective electronic control unit with us at equitable prices.
7. Diagnostic Tool - Use high grade diagnostic tools and equipment to resolve OBD code error. Buy new tools and equipment form us now!

There could be countless symptoms that would accompany this fault code. Willing to know some common symptoms of OBD Trouble Code P0AA1? Your wish is our demand. Have a look at them below:

Common Symptoms

• Check engine light might come into signal

Looking out for some ways with the help of which you can correct this fault code? Then you have arrived at the correct place. We are here to help you out, so you must check out the steps mentioned below as follows:

• It is necessary to perform proper service of the unsound PCM/ECM
• You must fix the defective HV control ECU
• The system main relay harness should be restored to working order
• Recondition the non-functioning system main relay circuit
• Adjust the flawed system main relay 

Don’t get tensed if you are still facing any of these issues as we care for our customers and that’s why we offer a good range of ecu, battery relay, hv control ecu, battery relay harness, battery relay switch, hv battery, pcm car, ecm car and engine control module and a lot more. We are sure that now all your issues would be resolved.

It is essential to diagnose this fault code. Here are some steps which a mechanic should follow for diagnosing the problem that triggered a P0AA1 code to be stored:

To start with, in such a condition, you are likely to hear loud noises like explosions from the rear of the vehicle while acceleration. The first step should be to check the carburetor to make sure that the fuel and air aptly balanced. If all this is functioning in order, then move onto thoroughly inspecting the distributor cap for any traces of cracks or hairline split as this can cause a backfire. Then the spark plugs should be inspected. Make sure that they are clean and are working in order. The engine gaskets should be checked for any traces of damage as they function for ensuring right gas exchange within the engine. The OBD-II code P0AA1 particularly refers to the camshaft (cam) timing. The engine light illuminates along with the stored code if the cam timing is over-retarded in this case.

Common Mistakes When Diagnosing The P0AA1 Code

• There can be a failure in the high voltage control module
• Wiring problems