QuestionMy 99 Elantra has codes: TPS P0122 Low Input, TPS P0121, EVAP Ctrl System Low P0452, EVAP Flow Fault P0441, EVAP Vent Malf P0446, and Manufac. P1605 Specific. What does this mean, and what is an estimated cost of repair?
AnswerP0121 and P0122 are most frequently caused by a faulty throttle position sensor. Check for proper power (5V) and ground at the TPS connector and verify none of the wires are broken in that area. If all this is okay, you've very good odds of repairing the issue by replacing the throttle position sensor.
P0441 indicates there is abnormal purge flow. I've never seen this code other than when the purge control valve is stuck open. P0446 (vacuum on evaporative system when not expected) and P0452 (low pressure reading from fuel tank pressure sensor) can be caused by the purge valve, so start with replacing that and clearing the trouble codes. If either the P0446 or P0452 return, you've additional issues that need to be addressed.
P1605 refers to an abnormal signal from the chassis acceleration sensor. Usually, this is caused by the sensor itself, but as was the case with the throttle position sensor codes, check for proper power (5V) and ground and for broken wires prior to replacing the sensor.
I'll also note that I've some concern that there may be a problem with the 5V power circuit controlled by the engine control module (ECM). If you do not have the proper 5V signal, the problem could be in the ECM or could be a partial short in one of the sensors powered off the 5V signal (such as the throttle position sensor, fuel tank pressure sensor, or chassis acceleration sensor). If 5V isn't present with the key on and unplugging a sensor restores the 5V, then that sensor is partially shorted.
As for cost of repair, that'll depend on the exact repairs needed and the time required to properly diagnose the issue. Even if this is known, the price will still vary widely based on geographic location, shop doing the repairs, and the manufacturer of the parts.
