2002 Lincoln Ls with 1504 and 1121 error codes

[mvbowens]

I have a 2002 lincoln ls v6 with the two error codes. It idles very high at 3000 rpm. Can you help

[shorod]

Welcome to the forum!

The codes you have make sense for the symptom.

All the following information is from the factory service manual.

Code P1504 means Idle Air Control (IAC) Circuit Malfunction. This code is likely set by one of the following:

• IAC circuit open
• VPWR to IAC solenoid open
• IAC circuit short to PWR
• IAC circuit short to GND
• Damaged IAC valve
• Damaged PCM

This DTC is set when the PCM detects an electrical load failure on the IAC output circuit.

The IAC solenoid resistance is from 6 to 13 ohms.

Code P1121 means Throttle Position (TP) Sensor Inconsistent with MAF Sensor. Likely causes of this code are:

• Air leak between MAF sensor and throttle body
• TP sensor not seated properly
• Damaged TP sensor
• Damaged MAF sensor

The PCM monitors a vehicle operation rationality check by comparing sensed throttle position to mass air flow readings. If during key ON engine running self-test the comparison of the TP sensor and MAF sensor readings are not consistent with calibrated load values, the test fails and a diagnostic trouble code is stored in continuous memory.

Drive vehicle and exercise throttle and TP sensor in all gears. A TP PID (TP V PID) less than 4.82 % (0.24 volt) with a LOAD PID greater than 55% or a TP V PID greater than 49.05% (2.44 volts) with a LOAD PID less than 30% indicates a hard fault.

-Rod