1996-1998 Saturn S-Series vehicles
Vehicle may experience the (MIL) SERVICE ENGINE SOON telltale On with DTCs P0340 and/or P0341.
DTCs P0340 and P0341 may be caused by incorrect resistance in the secondary ignition system. This incorrect resistance can cause the EI Module to incorrectly signal the cam position to the PCM.
The diagnostic information for DTCs P0340 and P0341 has been updated to included inspection of various secondary ignition components.
For complete description of circuit operation, refer to Circuit Description on page 6 of this bulletin.
DIAGNOSTIC AIDS
A cam pulse signal error may not effect engine operation.Important
Notes on Diagnostic Chart 1:
After saltwater spray test is complete, engine compartment must be rinses thoroughly
with clean water.Important
For complete description of circuit operation, refer to Circuit Description on page 6 of this bulletin.
DIAGNOSTIC AIDS
A cam pulse signal error may not effect engine operation.Important
Notes on Diagnostic Chart 2:
The cam signal is a 5 volt signal (circuit 633) that is pulled to ground to inform the PCM that #4 cylinder has fired on compression. A much higher voltage is needed to fire a cylinder that is on the compression stroke. The EI module monitors this firing voltage on the #1--4 coil to determine if cylinder #1 or cylinder #4 is firing. This signal, along with the double pulse received from the CKP sensor, synchronizes fuel timing.
Under normal operation, the 7X (CMP RESYNC) COUNTER continuously counts the notches in the crankshaft as it rotates, and resets to zero each time the CMP sensor detects the #4 cylinder firing. Therefore, the 7X (CMP RESYNC) COUNTER should continuously count from 0 to 14 with each two crankshaft revolutions. If the cam signal is missing, the 7X COUNTER will count to 255 and stay fixed and P0340 will set. If the cam signal is present too often, the counter will not reach 14 and a P0341 will set.
If the ignition secondary (coil, pair of spark plugs wires) has incorrect resistance, open or corrosion in the circuit that influences firing voltage, the EI module can incorrectly interpret these voltages and cause codes P0340 and/or P0341 to set.
DOHC (LL0) Engines | |
21024465 | Wire Asm - Splg (Cylinders 1 & 4) |
21024466 | Wire Asm - Splg (Cylinder 2) |
21024467 | Wire Asm - Splg (Cylinder 3) |
SOHC (L24) Engines | |
21024472 | Wire Asm - Splg (Cylinders 1 & 4) |
21024473 | Wire Asm - Splg (Cylinder 2) |
21024474 | Wire Asm - Splg (Cylinder 3) |
All Engines | |
21024473 | Module Asm - Elec Ign Cont |
16167763 | Coil Asm - Ign |
On 1996 vehicles, if spark plugs are replaced, and vehicle was equipped with
0.060 in gap plugs, all four spark plugs and "Vehicle Emissions Control Information
Label" must be replaced. Refer to Technical Information Bulletin 96-T-25,
"Engine Cranks but will not Start, or Engine Stalls Immediately After Start
Followed by Extended Cranking, and/or Ignition Misfire Resulting in DTCs P0300, P0301,
P0302, P0303, P0304."Important
To receive credit for this repair during the warranty coverage period, submit a claim through the Saturn Dealer System for one of the following depending on repair performed:
Case Type | Description | Labor Operation Code | Time |
VW | Wires, Spark Plug - Replace one or two | J4206 | 0.3 hrs |
Add: | A. To replace all spark plug wires | 0.1 hrs | |
VW | Module, Electronic Ignition (DIS) - Replace | J4343 | 0.6 hrs |
Add: | A. To replace all spark plug wires | 0.1 hrs | |
VW | Coil, Electronic Ignition Module - Replace | J4345 | -- |
Add: | A. To replace each additional coil | 0.2 hrs | |
B. To replace all spark plug wires | 0.1 hrs |
GM bulletins are intended for use by professional technicians,
NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to
provide information that could assist in the proper service of a
vehicle. Properly trained technicians have the equipment,
tools, safety instructions, and know-how to do a job properly and
safely. If a condition is described, DO NOT assume that the
bulletin applies to your vehicle, or that your vehicle will have
that condition. See your GM dealer for information on whether
your vehicle may benefit from the information. |
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