Engine Controls - Surge/Rolling Idle/No DTC's Present
TSB 11-8-2208/30/11
ROLLING IDLE AND/OR ENGINE SURGE WITHOUT
DIAGNOSTIC TROUBLE CODES (DTC) PRESENT
FORD:
2008-2009 Focus
This article supersedes TSB 09-16-6 to update the Part List and Service procedure.
ISSUE
Some 2008-2009 Focus vehicles may exhibit a rolling idle (400-1000 RPM) and/or engine surging condition with no diagnostic trouble codes (DTCs) present. This may be due to the Powertrain Control Module (PCM) commanding an erratic Exhaust Gas Recirculation (EGR) stepper motor signal.
ACTION
Follow the Service Procedure steps to correct the condition.
SERVICE PROCEDURE
1. Verify proper EGR signal is being commanded from the PCM.
NOTE
THIS PROCEDURE REQUIRES THE USE OF AN OSCILLOSCOPE.
2. Set the Oscilloscope settings by selecting the following:
a. Sense 50 A Probe.
b. Scale 500 mA /Div.
c. Coupling DC.
d. Filter 1.3 kHz.
e. Invert Off.
f. Display On.
If using Oscilloscope function on IDS:
3. Enter IDS Toolbox.
a. Select Oscilloscope Tools.
b. Select Oscilloscope.
c. Perform VMM Hookup to battery and IDS laptop using appropriate cables.
d. Connect 50 A inductive current probe (Rotunda Part Number 164-R9530) to channel 4 of VMM.
4. Next, select Timebase, then scale and set.
a. Scale 500 mS.
b. Zoom 100 %.
5. Press the oscilloscope run button. Zero the trace on the screen.
If using Oscilloscope function on IDS, the run button is the red person icon on the right side of the screen. The trace to be zeroed is blue. If the trace is not zeroed, press the blue number 4 button in the lower right portion of the screen and use the up or down arrow keys on the left side of the screen to move the trace. After the trace is zeroed press the run button again to stop the trace.
6. Select trigger and set.
a. Edge rising.
b. Mode one shot.
NOTE
IF USING OSCILLOSCOPE FUNCTION ON IDS, THE SOURCE IS CHANNEL 4.
7. Configure horizontal and vertical trigger levels. Move the vertical level trigger upward so that it is approximately halfway between the zero axis and the first division. This will position the trigger within the desired range (100-250 mA). Move the horizontal trigger position from the left side of the screen to the first division. (Figure 1)
If using Oscilloscope function on IDS, the T icon at the bottom right of the screen adjusts the vertical trigger level by using the arrow keys. Do not be concerned that the precise trigger position readout on IDS is expressed in voltage. This is because the current probe's raw signal is a voltage proportional to current.
8. Open the convolute harness at the EGR Stepper Motor connector and separate each of the 4 control wires. Place the current clamp around the single wire, circuit CE101, EGRMC1, (WH-VT) with the arrow of the current clamp pointing AWAY from the EGR connector.
9. Press the Oscilloscope Run Button.
10. Start the engine. A single waveform will be captured at startup and the scope will automatically stop. Compare the captured signal to the reference signal to determine if the stepper motor control signal is normal. Press the Run button before each engine start.
11. Repeat Step 5 through 10 for the remaining Stepper Motor Control signals: EGRMC2, CE102 (YE-BU)EGRMC3, CE1O3 (BU-BN)EGRMC4, CE104 (GN)
12. Does the waveform match the description and reference for a normal signal? (Figure 2)
a. A normal EGRMC waveform us 50/50 duty cycle for 16 cycles. (Figure 2)
b. Yes - Do not continue with this procedure.
Follow Workshop Manual, (WSM) and Powertrain Control Emission Diagnosis (PC/ED) diagnostics for rolling idle.
c. No - Proceed to Step 13.
13. If there is any variation in duty cycle, additional pulses and/or missing pulses, replace the PCM. (Figures 3-6)
Parts Block
WARRANTY STATUS: Eligible Under Provisions Of New Vehicle Limited Warranty Coverage And Emissions Warranty Coverage
IMPORTANT: Warranty coverage limits/policies are not altered by a TSB. Warranty coverage limits are determined by the identified causal part.
OPERATION DESCRIPTION TIME
110822A 2008-2009 Focus: Replace 1.0 Hr.
The PCM Includes Time
To Perform Diagnosis
Outlined In The Service
Procedure (Do Not Use
With Any Other Labor
Operations)
DEALER CODING
CONDITION
BASIC PART NO. CODE
12A650 42
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