SES Light Due to P2103 DTC - keywords C226 engine ETC FWD loss no P2118 power reduced stall TAC throttle wire voltage

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

On rare occasions, a SES light and reduced engine power may be encountered with a P2103 DTC. This could be due to a momentary loss of ignition voltage on terminal 6 of PCM connector 3 (Throttle Actuator Control (TAC) System Ignition Voltage). If a constant loss of ignition voltage occurs on this circuit, a P2118 should set.

If SI diagnostics do not isolate a cause for this concern, the following information may help:

1. Turn the ignition on and backprobe fuse # 4 (ETC S Fuse) in the underhood fuse block using a Fluke 87 DVOM set to min/max.
2. Depress the accelerator pedal to the wide open throttle position and note the minimum voltage reading on the Fluke 87. Ignition voltage should be present at all times.
3. If ignition voltage is lost, isolate the high resistance / voltage drop within the underhood fuse block or at fuse # 4 and repair as necessary.
4. If voltage is present, back probe terminal 6 of PCM connector 3 using a Fluke 87 DVOM set to min/max and repeat step 2. If ignition voltage is lost, measure the black and red TAC Ignition Voltage Circuit from fuse # 4 (ETC S Fuse) of the underhood fuse block and terminal 6 of PCM connector 3 for excessive resistance or voltage drop and repair as necessary.

Reference Information:

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.