2003 Jeep Grand Cherokee Ignition System Diagram

Jeep no start

Diagnose and fix Jeep no start

Most common causes of Jeep no start

Most Chrysler and Jeep no start problems can be traced to the following items:

• Crankshaft position sensor CKP (Fails to detect crankshaft movement)

• Camshaft position sensor CMP (Fails to detect camshaft movement)

• Auto Shutdown Relay (fails to provide power to the powertrain control module)

• Transmission Range selector (PCM must see park or neutral before it will allow start)

• Ignition switch actuator pin (Mechanical pin the runs between lock cylinder and ignition switch breaks—see below)

Test with scan tool

The easiest way to diagnose a Jeep no start is with a scan tool. Look for CMP and CKP signal. Receiving a CMP and CKP signal confirms that power is getting through the auto shutdown relay, to the PCM and to the CMP and CKP sensors and the PCM is receiving the proper signal.

If you don't have a scan tool with live data, you'll need a digital voltmeter to check for ASD relay power at the PCM, 5-volt reference at the CMP and CKP, good CMP and CKP ground and good CMP and CKP signal.

Begin troubleshooting with starter relay

Remove the starter relay from the power distribution center in the engine compartment. Check for battery power on two terminals in the relay socket with the key in the start position. If you don't see battery power, check fuses 28 15A and 8 40A in the PDC. If you see battery voltage, check for ground on pin 85 in the relay socket. The PCM provides ground to the starter relay control coil AFTER it determines the anti-theft system has passed the authentication test.

Test the auto shutdown relay

Remove the ASD relay from the power distribution center in the engine compartment. Check for battery power on two terminals in the relay socket with the key in the start position. If you don't see battery power, check fuses 6 30A and 26 15A in the PDC. If you see battery voltage, check for ground on pin 85 in the relay socket. The PCM provides ground to the starter relay control coil AFTER it determines the anti-theft system has passed the authentication test.

Jeep wiring diagram

Test for ASD power at the PCM

If the ASD is working properly, you should see battery power at the ASD terminal at the PCM.

jeep wiring diagram

CKP CMP wiring diagram jeep

Test for CMP and CKP reference and ground

Remove the CMP and CKP electrical connectors. Refer to the chart below and check for 5-volt reference voltage and good ground on the appropriate pins in the connector. Perform this test with the key in the RUN position. If power and ground are good, you'll have to check for spark and fuel injector operation. The only way to test the CMP and CKP sensors is with a scope.

Test for broken Ignition switch actuator pin

A broken ignition switch actuator pin may partially rotate the ignition switch, allowing the engine to crank but not fire up. This is a pretty common failure. Chrysler wants you to buy the complete steering column. But you can buy just the broken part. It's a Dorman 924-704.

jeep no start, dorman 924-704

Dorman 924-704 ignition switch actuator pin

Dorman 924-869 ignition switch, jeep no start

Dorman 924-869 ignition switch

Buy a Dorman 924-704 ignition switch actuator pin

Buy a Dorman 924-869 ignition switch

The ignition switch actuator pin from Dorman fits these vehicles:

2007 Jeep Liberty
2006 Chrysler Sebring
2006 Dodge Stratus
2006 Jeep Liberty
2006 Jeep Wrangler
2005 Chrysler PT Cruiser
2005 Chrysler Sebring Convertible
2005 Chrysler Sebring Sedan
2005 Dodge Neon
2005 Dodge Stratus Sedan
2005 Jeep Liberty
2005 Jeep Wrangler
2004 Chrysler PT Cruiser
2004 Chrysler Sebring Convertible
2004 Chrysler Sebring Sedan
2004 Dodge Neon
2004 Dodge Stratus Sedan
2004 Jeep Grand Cherokee
2004 Jeep Liberty
2004 Jeep Wrangler
2003 Chrysler PT Cruiser
2003 Chrysler Sebring Convertible
2003 Chrysler Sebring Sedan
2003 Dodge Neon
2003 Dodge Stratus Sedan
2003 Jeep Grand Cherokee
2003 Jeep Liberty
2003 Jeep Wrangler
2002 Chrysler Prowler
2002 Chrysler PT Cruiser
2002 Chrysler Sebring Convertible
2002 Chrysler Sebring Sedan
2002 Dodge Neon
2002 Dodge Stratus Sedan
2002 Jeep Grand Cherokee
2002 Jeep Liberty
2002 Jeep Wrangler
2001 Chrysler Prowler
2001 Chrysler PT Cruiser
2001 Chrysler Sebring Convertible
2001 Chrysler Sebring Sedan
2001 Dodge Neon
2001 Dodge Stratus Sedan
2001 Jeep Cherokee
2001 Jeep Grand Cherokee
2001 Jeep Wrangler
2001 Plymouth Neon
2001 Plymouth Prowler
2000 Chrysler Cirrus Sedan
2000 Chrysler Sebring Convertible
2000 Dodge Neon
2000 Dodge Stratus
2000 Jeep Cherokee
2000 Jeep Grand Cherokee
2000 Jeep Wrangler
2000 Plymouth Breeze
2000 Plymouth Neon
2000 Plymouth Prowler
1999 Chrysler Cirrus Sedan
1999 Chrysler Sebring Convertible
1999 Dodge Neon
1999 Dodge Stratus
1999 Jeep Cherokee
1999 Jeep Grand Cherokee
1999 Jeep Wrangler
1999 Plymouth Breeze
1999 Plymouth Neon
1999 Plymouth Prowler
1998 Chrysler Cirrus Sedan
1998 Chrysler Sebring Convertible
1998 Dodge Neon
1998 Dodge Stratus
1998 Jeep Cherokee
1998 Jeep Wrangler
1998 Plymouth Breeze
1998 Plymouth Neon
1997 Chrysler Cirrus
1997 Chrysler Sebring Convertible
1997 Dodge Neon
1997 Dodge Stratus
1997 Jeep Cherokee
1997 Jeep Wrangler
1997 Plymouth Breeze
1997 Plymouth Neon
1996 Chrysler Cirrus
1996 Chrysler Sebring Convertible
1996 Dodge Neon
1996 Dodge Stratus
1996 Plymouth Breeze
1996 Plymouth Neon
1995 Dodge Neon
1995 Plymouth Neon