There is no way to damage any component during the interrogation procedures just turn the ignition key off and start over.ġ990-1993 Corvette ECM and CCM codes can be accessed placing a jumper wire in ALDL positions A and G. There is no real concern if you are careful during the installation of the jumper wire. Our 1994-1996 ALDL has the jumper wire in place ready for CCM interrogation.ġ994-1996 Corvettes with the later designated OBDII (On-board Diagnostics) connector use battery voltage for scanner power, so it also has the potential for possible circuit damage. This connector position can harm other ALDL circuits if battery voltage is inadvertently jumped to a control circuit. It houses a fuel pump override lead that has battery voltage. Any loose strands could short another terminal.ġ990-1993 Corvettes use the first generation ALDL connector. Watch that the twisted wires stay inside the terminal during installation. This 1990-1993 ALDL has the jumper in place. The jumper wire is placed in the proper connector slots and the interrogation begins. The ALDL (Assembly Line Diagnostic Link) is used to access the codes with a jumper wire. For example, the CCM interaction is invaluable when diagnosing interior component or courtesy light problems and the VATS (Vehicle Anti-theft System). Although limited ECM data is available, it can point you in the right direction. In addition, ABS/ASR (Anti-lock Brake System/Acceleration Slip Regulation) and EBTCM (Electronic Brake Traction Control Module) trouble codes and data were introduced on the 1992-1996 Corvettes. When the 1990 Corvette debuted, GM introduced ECM (Engine Control Module) and CCM (Central Control Module) trouble codes.
#1991 ford diagnostic plug jumping code#
If spark is not present, then the next step is to make sure that the coil is getting power and the switching signal from the ignition module.Have you noticed “SYS” intermittently showing up in your 1990-1996 Corvette’s speedometer display? This means there is a trouble code stored in one of the on-board control modules. If spark is present directly on your Ford's coil's tower, then you can conclude that the coil's high tension wire is bad and needs to be replaced (along with all of the spark plug wires). This spark test result will let you know if the high tension cable is bad and not letting spark thru' to the distributor cap (this happens quite a bit) or will let you know that you need to continue to the next test. In this test step, you're gonna' test for spark directly on the ignition coil and thus bypass the coil's high tension wire. IGNITION COIL TEST 2: Testing For Spark Directly On Coil'S Tower Now, don't worry, this article will help you find out, go to: IGNITION COIL TEST 2: Testing For Spark Directly On Coil's Tower. The wire could be bad or the ignition coil could not be receiving its switching signal from the ignition control module or the coil could really be fried.
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This test result tells you that something is wrong but doesn't condemn the ignition coil or the high tension wire as bad just yet.
#1991 ford diagnostic plug jumping how to#
How To Troubleshoot A No Start (Ford 4.9L, 5.0L, 5.8L).ĬASE 2: You got NO spark.
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The following tutorial will provide you with other diagnostic/troubleshooting ideas to solve your Ford's no-start condition: Since the ignition coil's job is to create spark and your spark tester has confirmed that the ignition coil is sparking, then you can eliminate the ignition coil as defective. This spark test result means that the ignition coil and its high tension wire are good and not the cause of your Ford pick up's (or van or SUV) no-start condition. OK, let's take a look at what your test results mean:ĬASE 1: You got spark. The HEI spark tester will give you one of two results: spark or no spark.