My 2000 Nissan Altima started exhibiting a frustrating issue: it would stall, particularly when accelerating or under load. Despite stalling, it would restart, only to stall again shortly after. The “Service Engine Soon” light was illuminated, signaling a problem. Hoping to get to the bottom of it, I enlisted the help of a friend with an OTC scanner. However, after connecting his scanner, the car wouldn’t even start – it would turn over, but just wouldn’t fire up. Perplexed, we left it overnight.
The next morning, surprisingly, the car started again. I managed to drive it home and performed some basic maintenance, replacing the fuel filter and changing the oil. For a day, it seemed like the issue was resolved. Unfortunately, the stalling returned the following day while my daughter was driving. This prompted me to delve deeper into possible causes. After extensive online research, I decided it was time to invest in my own OBD2 scanner and ordered an Ancel 410 from Amazon for $73.00.
While waiting for my new scanner to arrive, I continued my troubleshooting efforts, turning to YouTube for guidance. There, I discovered a common issue: vacuum leaks caused by rodents. Upon inspection, I found a vacuum hose that had indeed been chewed through, likely by a mouse or rat that had taken up residence in my engine during the winter. I had previously removed a nest, which now seemed to be connected to the problem. Replacing the damaged hose appeared to resolve the stalling issue. The “Service Engine Soon” light remained on, but the car was running smoothly through several test drives. It seemed the vacuum leak was the culprit behind both the stalling and the warning light.
Alt text: A detailed view of a car engine compartment highlighting various vacuum hoses, crucial components often susceptible to leaks and damage.
Just when I thought the problem was solved, my friend returned with his OTC OBD scanner to read the error codes and finally extinguish the “SES” light. He successfully retrieved the following codes: P0100, P0505, P0325, P1490, P0446, and P0464. However, incredibly, reconnecting the OBD scanner caused the car to revert to its no-start condition, even though it had been running perfectly moments before. The “SES” light was still stubbornly on, and now the car was refusing to start again!
Back to YouTube I went, searching for answers. This time, I learned about a peculiar issue: OBD scanners can sometimes interfere with the Engine Control Module (ECM), requiring a hard reset. The solution, I discovered, is to perform a hard reset by disconnecting both battery terminals and briefly connecting them together for about 10 seconds (ensuring they are fully removed from the battery). This process discharges the capacitors in the ECM, effectively resetting it. Following these instructions, I performed the hard reset, and thankfully, the car started right up again.
Alt text: Illustration of disconnecting car battery terminals using a wrench, a key step in performing a hard reset of the vehicle’s ECM.
This experience highlighted a valuable lesson about using OBDII diagnostic readers. While incredibly helpful for diagnosing issues and retrieving error codes, they can, in rare cases, cause unexpected problems. Understanding how to perform an ECM hard reset can be a crucial skill for any car owner dealing with electrical or sensor-related issues, especially when using diagnostic tools. And although the term “Obdii Diagnostic Reader While Driving” might suggest using these tools in motion, it’s clear that their primary function is for diagnostics when issues arise, sometimes even resolving unexpected scanner-induced problems through methods like ECM resets.
