Jeep Cherokee 1988 Quick Start Manual page 8

3) Voltage should be 4.5-5.5 volts. Same voltage should also
be at terminal C-14 of ECU wire harness connector. Using Diagnostic
Tester (M.S. 1170), test MAP sensor ground circuit at terminal D-3
and terminal "A" of sensor connector.
4) Using an ohmmeter, test MAP sensor ground circuit at ECU
connector between terminal D-3 of ECU connector and terminal B-11
with an ohmmeter.
5) If ohmmeter or diagnostic tester indicates an open
circuit, inspect for a defective sensor ground connection, located on
right side of cylinder block. If ground connection is good, ECU may
need to be replaced.
Fig. 5: MAP Sensor Test Points
Courtesy of Chrysler Motors.
O2 Sensor Heating Element Test
Disconnect O2 sensor connector. Connect an ohmmeter to
terminals "A" and "B" only (marked on the connector) of O2 sensor
connector. Resistance should be between 5 and 7 ohms. Replace sensor
if ohmmeter indicates an infinity reading.
CTS Test