Code 53, Intermittent 4X Signal From Ignition Module: Notes

Code will set if Codes 19 and 35 are not set, 4X reference pulses have not been seen by PCM for 0.4 second and engine speed is greater than 568 RPM.

1. Checks to see if Code 35 is also set. a faulty reference low circuit will cause multiple codes.
2. Checks power to ignition module.
3. Checks if ignition module can produce a 4X reference pulse. If system is operating properly, at least a 30 hertz signal will be measured.
4. There is an open at fuse block. Also check terminal contact.
5. Checks for open or short to ground in 4X circuit.