MIL ON - DTCs 29 or 69 With No System Fault
90jaguar05VCM FUEL FAIL SECTION: 18
CODES 29 AND 69 No: 14
Model: 1990 MY Date:
SEDAN RANGE JULY, 1990
KEY POINTS:
FALSE WARNINGS
It is possible for the CHECK ENGINE warning to illuminate and for "Fuel Fail" codes 29 or 69 to be displayed on the VCM when no engine management faults exist.
To prevent the unnecessary replacement of components due to false CHECK ENGINE warnings associated with codes 29 and 69, refer to the following information:
"Fuel Fail" Code 29:
Code 29 indicates failure of an engine management system ECU self test. This may occur when the vehicle battery is in a low state of charge and does not necessarily indicate a faulty ECU.
If "Fuel Fail" code 29 is displayed:
^ Check the condition of the vehicle battery and connections. Charge the battery if necessary (refer to Technical Bulletins section 86, numbers 56 and 66).
^ Disconnect the battery to erase code 29 from the ECU memory.
NOTE: JDS will not erase code 29.
^ Reconnect the battery.
^ Check the connections to the engine management system (EMS) ECU.
^ Start the engine several times to check for recurrence of "Fuel Fail" code 29.
If the CHECK ENGINE light does not illuminate, no further action is necessary.
If "Fuel Fail" code 29 does recur, replace the EMS ECU and report the fault conditions (i.e. What is the battery voltage?; When did CHECK ENGINE light illuminate?) via a Product Quality Report.
"Fuel Fail" Code 69:
Code 69 indicates the engine starting (low engine rpm) in DRIVE or a high engine load above 3550 rpm in PARK or NEUTRAL.
In PARK or NEUTRAL, a ground is provided to pin LI59-3 at the EMS ECU by the decoder module, which receives gear position signals from the transmission rotary switch.
"Fuel Fail" code 69 may be illuminated when the ignition is switched from off to start in one motion. This is due to a lag in the "wake-up" of the decoder module which permits the EMS ECU to detect engine cranking prior to receiving the PARK/NEUTRAL signal. This condition is even more likely to occur when battery voltage is low.
False fault code 69 warnings can be prevented by using the, following procedure:
^ Switch the ignition
^ Wait until the instrument panel lights illuminate.
^ Start the engine.
If code 69 is displayed:
^ Check the vehicle battery voltage and connections. Charge the battery if necessary (refer to Technical Bulletins section 86, numbers 56 and 66).
^ Erase code 69 from the EMS ECU memory through JDS or by disconnecting the vehicle battery.
^ Using the above mentioned procedure, start the engine several times and roadtest the vehicle.
If fuel fail code 69 does not recur, no further action is necessary.
If "Fuel Fail" code 69 does recur, use the following procedure:
^ Check gearshift cable adjustment.
^ Check the rotary switch position.
^ Check the pin connections at the rotary switch harness connector (GB1), the decoder module (GB6) and the EMS ECU (LI59).
^ If the cable and switch are adjusted properly and no apparent pin/wire damage exists, perform a JDS Engine Management test.
Report any identified fault conditions via a Product Quality Report.