Code 24
IGNITION DRIVE CIRCUIT - DTC 24
The ECM looks for the ignition drive output levels to be outside the normal range for both the ON and the OFF signal.
The ECM ignition drive output controls the ignition module switching of the low tension circuit. The drive signal is a square wave output that can be monitored with an oscilloscope.
The ECM will flag DTC 24 if the drive ON signal voltage is less than 4.5 volts; or if the OFF signal voltage is greater than 0.1 volt.
Output Signal:
Conditions Required For DTC 24 Flagging
Ignition Ignition - ON.
Ignition drive ON signal voltage - Voltage less than 4.5 volts.
Ignition drive OFF signal voltage - Voltage greater than 0.1 volt.
Response time - 600 milliseconds.
Limp Home Default
None
Possible Faults
- Low battery voltage.
- Poor connection at ECM or ignition module.
- Water ingress at ECM blue connector (WR wire).
- Short circuit in WR wire between ECM and ignition module.
- Defective ignition module.
- Defective ECM.
Diagnostic Notes
1. The ignition module in 1990 MY XJ6 vehicles has 4 wires plus a ground; all later vehicles have 3 wires plus ground. The 3-wire module can be used to replace the 4-wire module without modification.
2. The ignition module and heat sink plate are replaced as a unit. If the module and heat sink plate are separated. use heat sink compound during reassembly.
Circuit Diagram
Circuit Diagram:
Flow Chart: DTC 24
�ǓFlow Chart: DTC 24:
