1991 Jeep Cherokee LimitedFACTORY OEM SERVICE PROCEDURE

Dr-1A: Checking System For Faults

NOTE: Battery must be fully charged and at rated capacity before performing any driveability test procedure. If vehicle starts and stalls repeatedly, perform NO START TEST NS-2A: CHECKING FUEL DELIVERY SYSTEM  .
  1. Ensure ignition is off. Connect DRB-II to engine diagnostic connector. Connector is located on left side of engine compartment, near SBEC. See 1.
  2. Without starting engine, turn ignition on and access READ FAULTS function of DRB-II FUEL/IGN MENU. If DRB-II reads NO FAULTS, go to step 4). If DRB-II reads INTERNAL CONTROLLER FAILURE, replace engine controller and perform VERIFICATION PROCEDURE VER-2  .
  3. If DRB-II reads ENGINE IS COLD TOO LONG, service cooling system as required to bring system within specification and then perform VERIFICATION PROCEDURE VER-3  .
  4. Start engine and allow it to reach normal operating temperature. Manually run engine at 2000 RPM for at least 10 seconds and allow engine to return to idle.
  5. If vehicle is equipped with air conditioning, place A/C-heater blower fan on low speed and turn A/C system on. If vehicle stalls when A/C system is turned on, go to next step. If vehicle does not stall, go to step 8).
  6. Turn ignition off. Disconnect 60-pin engine controller connector. Inspect connector for proper wire placement, corrosion, damaged terminals, or pushed-out pins. Repair as necessary and go to next step.
  7. Turn ignition on. Place DRB-II in voltmeter mode. Probe engine controller connector Dark Blue wire (pin No. 9). If reading is less than 10 volts, repair open in Dark Blue wire. If reading is more than 10 volts, replace engine controller and perform VERIFICATION PROCEDURE VER-2  .
  8. If vehicle is equipped with an automatic transmission, step on brake pedal and shift through all gears. Return shift lever to PARK position. Use DRB-II to read fault messages and go to next step.
  9. If DRB-II once again reads NO FAULTS, check for technical service bulletins that relate to this driveability problem. If no related technical service bulletins are found, perform DRIVEABILITY TEST DR-26A: CHECKING SECONDARY IGNITION & TIMING  .
  10. If pertinent technical service bulletins are found, perform the corrective action given. If driveability problems continue after performing corrective action, perform DRIVEABILITY TEST DR-26A: CHECKING SECONDARY IGNITION & TIMING  .
DRB-II FAULT MESSAGES

DRB-II Message (1) Hard Fault (2) Intermittent Fault
A/C Clutch Relay Circuit DR-22A  DR-35A 
Automatic Idle Speed Motor Circuits DR-15A  DR-37A 
Charge Temperature Sensor Voltage High DR-11A  DR-36A 
Charge Temperature Sensor Voltage Low DR-12A  DR-36A 
Controller Failure EEPROM Write Denied DR-25A  DR-25A 
Controller Failure EMR Miles Not Stored DR-25A  DR-25A 
Coolant Sensor Voltage Too High DR-9A  DR-36A 
Coolant Sensor Voltage Too Low DR-10A  DR-36A 
Injector No. 1 Control Circuit DR-16A  DR-38A
Injector No. 2 Control Circuit DR-17A  DR-38A
Injector No. 3 Control Circuit DR-18A  DR-38A
Injector No. 4 Control Circuit DR-19A  DR-38A
Injector No. 5 Control Circuit DR-20A  DR-38A
Injector No. 6 Control Circuit DR-21A  DR-38A
MAP Voltage Too High DR-5A  DR-36A 
MAP Voltage Too Low DR-4A  DR-36A 
No ASD Relay Voltage Sense At Controller DR-24A  DR-24A 
No Change In MAP From Start To Run DR-3A  DR-36B 
No Vehicle Speed Signal DR-6A  DR-6A 
O2 Signal Shorted To Voltage DR-8A  DR-8A 
O2 Signal Stays At Center DR-7A  DR-7A 
O2 Signal Stays Below Center (Lean) DR-26A  DR-26A 
O2 Signal Stays Above Center (Rich) DR-26A  DR-26A 
Radiator Fan Relay Circuit DR-23A  DR-35A 
Slow Change In Idle MAP Signal DR-2A  DR-36A 
Throttle Position Sensor Voltage High DR-13A  DR-36A 
Throttle Position Sensor Voltage Low DR-14A  DR-36A 
(1) Key counter is "0".
(2) Key counter is greater than "0".
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.