Having become the proud owner of a 2000-2001 L series shop manual (and because Engineers just like to find out how things work) I was looking for the source of some radio interference. I hit a low hanging tree branch a while back and the radio has gotten more susceptible to interference when the engine is running (not spark noise but HF computer type noise). Suspected that the antenna was damaged and was going to borrow one to swap out but found a more exact method, the onboard radio diagnostic. My car has the AM/FM/CD/Tape uplevel model. (bought it used and that's the way it came). Enter the diagnostic from the radio on (either am or fm) and simultaneously press RCL + 1 + 6 while pressing off button. Radio will beep to show diagnostic mode. Display will show 'DTC' Diagnostic trouble code memory. Press RCL to show E-01 and RCL again to show the number of errors experienced. Press am/fm to back up to E-xx and use seek to select another code. continue as before to find all codes. When done, hit am/fm to return to DTC top menu. Error codes: E-01 Tape eject error E-02 Tape play error E-03 Tape insertion error E-04 CD eject error E-05 CD play error E-06 CD insertion error E-07 CD changer error E-08 CD changer magazine loading error E-09 CD changer play error ============== Back at the DTC display, hit the SEEK rocker to sequence to the next diagnostic: DTC => TT => LCD => KEY => EQ:__ => ANT => CDCH => CC At each diagnostic, hit RCL to enter and am/fm to back out. TT: test tone. hit RCL to begin test. A 100Hz tone is sent to the left front speaker for 2 seconds followed by a 3kHz tone. Press the TUNE button to cycle from the LF to RF to LR antd to RR speakers Press am/fm to escape back to menu. LCD: Display segment test. Press RCL to light all segments. Press am/fm to escape to menu. Key: Key test. Press RCL and press keys. A beep is heard for each key press. Press am/fm to escape to menu. EQ: Displays which audio system the radio is connected to. RCL am/fm ANT: Press RCL to display the received signal strength of the last station tuned. Tuning controls are locked out for this test so set a station of interest before entering diagnostic mode. Press am/fm to escape to menu. CCDH: CD changer communication. Hit RCL to test communication. If changer not installed, ERR displays. Press am/fm to escape to menu. CC: Clear Error codes. Clears error codes displayed under DTC. Press RCL and display shows OK?. press RCL again for 2 seconds until confirmation tone is heard to clear codes. Press am/fm to escape to menu. To exit diagnostic mode, hit power off. ============== Word of caution, watch out for inadvertantly setting the Theft Deterrent security mode. Ignition on, radio off, press and hold buttons 5 and 6 until the radio shows _ _ _ _. This procedure is given in the owner's manual. Radios are delivered in the unsecured state. If the secured mode is chosen, you have to enter a 4 digit code to lock it. Owner will need to make the code available for service personnel or unsecure it for service. Sounds like a pain.
