2001 Honda Accord 2.3L P0122 Code: Transmission Revs to 3500 RPM for Shifting
Hi there, I own a 2001 Honda Accord 2.3L 4-cylinder. The issue I'm experiencing is that when the Check Engine Light (CEL) is on, my transmission revs up to 3500 RPM in order to shift from first to second, then third, and finally fourth gear. I took it to a repair shop where they scanned the vehicle and found a P0122 code. I tested the throttle position sensor (TPS) myself using a multimeter. I checked the 5V reference voltage, ground connection, and signal wire. The 5V supply is stable on both upper and lower wires. The middle signal wire shows a reading of approximately 4.5V at wide open throttle (WOT), increasing smoothly with acceleration—this indicates the TPS appears to be functioning correctly. The shop stated that the transmission system did not produce any diagnostic codes. I'm concerned whether this is a sensor issue, a control module problem, or if the vehicle is entering fail-safe mode. Could the P0122 code be causing the transmission to behave abnormally? Any insights would be greatly appreciated. Thanks in advance!
The system may be operating in fail-safe or limp mode when the Check Engine Light is on—do not attempt to force shifts at high RPMs (like 3500 RPM), as this can cause further damage. A proper TPS setup has three wires: 5V reference, ground, and signal. At idle, the signal should read around 0.5V; at WOT, it should reach about 4.5V. The reading must increase smoothly with throttle input—any abrupt changes suggest a faulty sensor or wiring. Note: You mentioned checking for 12V on the upper and lower wires—this appears to be incorrect. TPS sensors do not operate on 12V; they use a 5V reference. Double-check your multimeter settings and connections. Consider reviewing the freeze frame data from the scan, as it may contain critical information about when the fault occurred. Also, is this vehicle stock (no modifications)? Any other symptoms like hesitation, stalling, or poor fuel economy? This could help narrow down the root cause.