Hesitation while accelerating

Tiny
BLESSING EWOBOR
  • MEMBER
  • 2003 MERCEDES BENZ C240
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 145,324 MILES
Good morning, this vehicle hesitates while accelerating and when one decelerate for something like bump on the highway. The vehicle won't be able pass (climb over) the bump, at this point, you might press down the gas pedal, the engine speed will keep on increasing but the transmission is not responding. I have to put the transmission in park position, off the engine on the highway and restart the engine again, then place the transmission in drive position before it can overcome that obstacle. I scanned the vehicle the only code I saw on the transmission system is shown below. The gear box was newly changed, could the problem be the gear box itself or what?
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Thursday, December 10th, 2020 AT 4:38 PM

4 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

It sounds like the transmission is slipping. Have you checked the transmission fluid condition and level?

There are many things that can cause the code. Take a look through this list.

1. Possible causes and remedial action when fault code P2502 is displayed.

Test 1.1: Notes on repair : Remedial actions must be processed in sequence.

Test 1.2: The oil level in the automatic transmission is too low.

Test 1.3: Output speed has exceeded the limit value.

Test 1.4: The oil filter is not installed in the automatic transmission.

Test 1.5: Incorrect rear axle ratio.

Test 1.6: Incorrect variant coding in component N15/3 (ETC [EGS] control unit).

Test 1.7: Component Y3/6y1 (Modulating pressure control solenoid valve) is blocked as a result of the effect of a foreign body.

Test 1.8: Control valve, shift valve, or command valve of the appropriate gearshift are blocked by the effect of a foreign body.

Test 1.9: Circlip of ball bearing of output shaft missing or has jumped out of groove.

Test 1.10: Circlip of axial bearing K3 missing or has jumped out of groove.

Test 1.11: Circlip of dished washers B2/B3 has jumped out of groove.

Test 1.12: Seal of clutch K3 is faulty because of wear of the plain bearing between input shaft and output shaft.

Test 1.13: Internal fault in component Y3/6 (electrical control module):

1.1. Notes on repair : Remedial actions must be processed in sequence.

____________________________

If this problem just started when the transmission was replaced, first confirm the fluid is full. If that is okay, it is likely an internal mechanical issue.

Here are directions for checking level and condition. The attached pics correlate with the directions.

_________________

Checking condition of ATF (Initial Evaluation)
1. Check ATF level, correct fluid level as necessary.
2. Review section 0 See: Automatic Transmission/Transaxle > Scan Tool Testing and Procedures > Scan Tool Connecting [0]

NOTE: Prior to performing any repairs, readout the DTC memory from the transmission control module using the HHT (see Section 12). See: Automatic Transmission/Transaxle > Reading and Clearing Diagnostic Trouble Codes > Displaying & Reading Trouble Codes (DTC Memory [12])

Visually inspect condition of transmission fluid.
- Contamination (excessively black transmission fluid color, pungent/burnt smell)
- Water in transmission fluid (milky white discoloration, streaked appearance)
- Metal shavings (metal particles, metal pieces)

The initial dosage of the red pigment in the ATF was too low. Since 10/97, the use of a higher dosage of red pigment in the ATF, has resulted in more stable red pigmentation. A purely brown or black coloring of the ATF does not have an effect on the friction value or function of the ATF, therefore, no fault is indicated regarding the ATF color.
ATF fluid which smells burnt points to a slipping Brake/clutch assembly. After finding the cause (loss of ATF, or seized servos etc.) And removing same, replace both the faulty items and the ATF.

Abrasion particles in the ATF:
Due to the relative movement between the transmission components after a short running distance, a fine "vail" of abrasion particles (gray for aluminum, yellow for brass) can be found in the transmission oil pan.
This "vail" abrasion does not effect the proper function of the transmission.
If there is however, found in the transmission oil pan, an extremely fine abrasion (graphite residue which when smeared on paper leaves a gray streak) or larger metal shavings (in the millimeter size range) then there is a mechanical fault within the transmission. Based on the complaint, the corresponding components of the transmission or the entire transmission must be replaced. When repairing the transmission, it is important to flush the oil cooler and the transmission hoses afterwards and the replace the ATF with fresh ATF. Replace the torque converter only if upon draining the ATF, metal shaving are found in the ATF

3. Inspect automatic transmission for external oil leaks (Determine source of fluid leak and repair).

ATF level check
When checking the ATF level, the temperature must be min. 60 C.
The current ATF temperature as part of the ATF level check can only be read out using the HHT, with the transmission selector lever in "R, D, 4, 3, 2, 1".

Initial Evaluation Illustrations

See pics 1.
Extremely fine aluminum and/or brass abrasion particles
Transmission is serviceable

See pic 2

Extremely fine graphite like abrasion particles
Mechanical damage to transmission

See pic 3

Large metal shavings, in millimeter size
Mechanical damage to transmission

____________________

Let me know if this helps or if you have other questions.

Take care,
Joe
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Thursday, December 10th, 2020 AT 9:28 PM
Tiny
BLESSING EWOBOR
  • MEMBER
Thank you,
from what you sent Note: Prior to performing any repairs, readout the DTC memory from the transmission control module using the HHT (see Section 12). The HHT, what does it mean?
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Friday, December 11th, 2020 AT 3:04 AM
Tiny
BLESSING EWOBOR
  • MEMBER
Test driving the vehicle today more codes were found on its "Electronic Transmission control", they are shown below.
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Friday, December 11th, 2020 AT 7:11 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
HHT is a reference to a scan tool for Mercedes. They are recommending that you retrieve any trans codes before you make repairs.

________________

Here are the directions for diagnosing the issue related to the 2108. This is the likely cause of the problem. It could be an electrical failure or mechanical in the valve body. The attached pics correlate with the directions.

_______________

2003 Mercedes Benz C 240 Sedan (203.061) V6-2.6L (112.912)
The internal electrical check of component Y3/6y2 (Shift pressure control solenoid valve) has failed.
Vehicle ALL Diagnostic Trouble Codes ( DTC ) Testing and Inspection P Code Charts P2108 722.6 (5-gear) ETC Main as of 2001 The internal electrical check of component Y3/6y2 (Shift pressure control solenoid valve) has failed.
THE INTERNAL ELECTRICAL CHECK OF COMPONENT Y3/6Y2 (SHIFT PRESSURE CONTROL SOLENOID VALVE) HAS FAILED.
The internal electrical check of component Y3/6y2 (Shift pressure control solenoid valve) has failed.

Possible cause:

- Y3/6y2 (Shift pressure control solenoid valve)
Affected functions:

- Engine diagnosis
- Automatic transmission Function

Test 1: Check component Y3/6y2 (Shift pressure control solenoid valve).

1. Check component Y3/6y2 (Shift pressure control solenoid valve).
Operation number of operation texts and work units or standard texts and flat rates:27-0641Test prerequisites

- Erase fault memory.
- The power supply of component is okay.
Test sequence

- Switch off ignition.
- Connect socket box.
- Measure resistance with multimeter between sockets [2.37] 37 and [2.38] 38 of the 126-pole socket box tester.
Specified value:

- Resistor[4.0.8.0]ohms
Question

- Is the measurement value okay?

See pic 1

YES
The measurement value is okay. Possible cause

- Internal fault in component N15/3 (ETC [EGS] control unit):
Possible remedy

- Replace component N15/3 (ETC [EGS] control unit).
Notes on submitting warranty or goodwill claims

- SEAG damage code (7 digits):54 553 73
End of test

see pic 2

NO
Test prerequisites

- The measurement value is not okay.
Additional measures

- Disconnect socket box.
- Separate plug connection at transmission.
- Measure resistance.
Test sequence

- Measure resistance with multimeter between 10 and 6
Specified value:

- Resistor[4.0.8.0]ohms
Question

- Is the measurement value okay?

See pic 3

YES
The measurement value is okay. Possible cause

- Line between component 'Y3/6 (electrical control module)' and control unit N15/3 (ETC [EGS] control unit) faulty
Possible remedy

- Test cable for short circuit to ground.
- Test cable for short circuit to positive.
- Test cable for open circuit.
Notes on submitting warranty or goodwill claims

- SEAG damage code (5 digits):27 023
End of test

NO
Test prerequisites

- The measurement value is not okay.
Additional measures

- Remove component as per the repair instructions.
- Repeat internal resistance measurement on component when removed.
Test sequence

- Measure resistance with multimeter between 1 and 2
Specified value:

- Resistor[4.0.8.0]ohms
Question

- Is the measurement value okay?

See pic 4

YES
The measurement value is okay. Possible cause

- Fault in supporting body of component Y3/6 (electrical control module)
Possible remedy

- Replace supporting body on component Y3/6 (electrical control module).
Notes on submitting warranty or goodwill claims

- SEAG damage code (7 digits):27 264 73
End of test

see pic 5

NO
The measurement value is not okay. Possible cause

- Component is defective.
Possible remedy

- Replace component.
Notes on submitting warranty or goodwill claims

- SEAG damage code (7 digits):27 226 73
End of test

see pic 6

__________________________________

I have to be honest. Chances are this is a pressure-related issue. Since the transmission is newly replaced, I would contact the person that did the work.

Let me know.

Joe
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Friday, December 11th, 2020 AT 9:58 PM

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