Questions and Answers

Jeep Cherokee Codes 11, 12 And 42 Q. I have a 1994 Jeep Cherokee, 4.0 liter with 112,000 miles, automatic transmission, 4WD, ABS brakes, A/C and power steering. Jeep ran fine, parked in the driveway, would turn over, but wouldn't start. I had no spark. The Automatic Shut Down relay seems to not get enough power to it to work the relay. The problem seems to be on the ground side.

I am unsure of what I'm looking at when I trace back to find the problem. There is a box on the fender well, driver side that the wiring harness plugs into. Is this the PCM, or is it located near the steering column under the dash? I have been unable to find a wiring diagram that shows me the complete path.

When I checked codes, I get 12, 11 and 42. The coil, and camshaft position sensor in the distributor have been replaced. Would the crankshaft position sensor cause this problem? How do I check the CPS? Any help you could give me would be great. I just discovered this web site and it has been great!

Thanks,
Mike

A. Here is how to test the ASD relay and wiring.

RELAYS-OPERATION AND TESTING:

The following operations/tests apply to these relays only:

Automatic Shutdown (ASD) , Fuel Pump and Ballast Bypass. For operations/tests on all other relays refer to the appropriate test.

OPERATION:

• The relay terminal numbers can be found on the bottom of the relay.
• Terminal number 30 is connected to battery voltage and can be switched or B + (hot) at all times.
• Terminal number 87A is connected (a circuit is formed) to terminal 30 in the de-energized (normally OFF) position.
• Terminal number 87 is connected (a circuit is formed) to terminal 30 in the energized (ON) position. Terminal number 87 then supplies battery voltage to the component being operated.
• Terminal number 86 is connected to a switched power source.
• Terminal number 85 is grounded by the Engine Controller.

TESTING:

1. Remove relay before testing.
2. Using an ohmmeter, perform a resistance test between terminals 85 and 86. Resistance value (ohms) should be 75 ±5 ohms for resistor equipped relays.
3. Connect the ohmmeter between terminals number 87A and 30. Continuity should be present at this time.
4. Connect the ohmmeter between terminals number 87 and 30. Continuity should not be present at this time.
5. Use a set of jumper wires (16 gauge or smaller). Connect one jumper wire between terminal number 85 (on the relay) to the ground side (-) of a 12 Volt power source.
6. Attach the other jumper wire to the positive side (+) of a 12V power source. Do not connect the jumper wire to relay at this time.

CAUTION: Do not allow the ohmmeter to contact terminals 85 or 86 during these tests. Damage to ohmmeter may result.

7. Attach the other jumper wire (12V +) to terminal number 86. This will activate the relay. Continuity should now be present between terminals number 87 and 30. Continuity should not be present between terminals number 87A and 30.
8. Disconnect jumper wires from relay and 12 Volt power source.

If continuity or resistance tests did not pass replace relay.

The Powertrain Control Module (PCM) and connector are located in the engine compartment, mounted to the inner fender, next to the air cleaner housing.

• DTC 11 - No reference signal during engine cranking. No camshaft reference signal was detected during engine cranking.
• DTC 12 - Battery disconnect. Battery input to PCM disconnected during last 50 key starts.
• DTC 42 - ASD relay control circuit. An open or shorted condition detected in the auto shut down relay circuit.