How to Fix P1604 Trouble Code?
4 Answers
This trouble code indicates a starting system malfunction. Since professional tools are required for diagnosis and repair, it is recommended to visit an auto repair shop or 4S dealership for inspection. Below is some information about the P1604 trouble code: 1. The P1604 trouble code signifies a starting system malfunction in Chinese. There are generally two causes for this code: unsuccessful starting due to insufficient oil pressure, or difficulty starting the vehicle after disconnecting the battery cables. 2. After troubleshooting the vehicle issue, the trouble code must be cleared. When clearing the trouble code, strictly follow the specific clearing method prescribed for your vehicle model. Never attempt to clear the code by simply disconnecting the negative terminal of the battery.
My car also threw a P1604 trouble code before, and I was really anxious at that time. This code actually indicates an internal issue with the engine control unit (ECU) – it could be a malfunction of the ECU itself or poor wiring connections. First, I disconnected the negative battery terminal and waited a few minutes before reconnecting it to try resetting the system. Unexpectedly, the check engine light remained on, so I popped the hood to inspect the battery terminals for looseness or corrosion. After struggling with it for a while without success, I had no choice but to drive it to the repair shop. The mechanic used a diagnostic tool and concluded that the ECU module had failed and needed replacement, which cost me nearly two thousand yuan. This kind of fault shouldn't be delayed – in severe cases, it can cause the car to stall suddenly. Safety always comes first!
Auto repair shops often encounter the P1604 fault code, and the diagnostic procedure is quite systematic. First, I use a professional diagnostic scanner to read the fault information to confirm whether it's an internal ECU component issue. Next, I check if the battery voltage is stable—around 14 volts is considered normal. Then, I inspect the wiring for loose connections, paying special attention to the pin conditions on the ECU connector. If the wiring is intact but the fault persists, it usually means the ECU program needs to be refreshed or the module replaced. The trickiest cases involve older cars with aged wiring—last time, a customer messed with the wiring themselves and ended up blowing a fuse. My advice: don’t attempt DIY fixes; leave it to a professional mechanic for peace of mind.
Don't take the P1604 code lightly, as it indicates a malfunction in the vehicle's computer core components. My handling process was: immediately stop to check the dashboard status and look up the fault code meaning on my phone. Not daring to continue driving, I directly called for a tow truck to take it to the 4S shop. After inspection, they said it was caused by corrosion on the ECU's internal circuit board leading to a short circuit, requiring a complete replacement. Although the price was painful, safety comes first. Now, I get a full vehicle circuit inspection every six months as a preventive measure.
