Recall - D632 Engine Control Unit
Bulletin: R91-001CASection: RECALL
Dated: 02/27/91
Applicable to: CALIFORNIA ONLY
SUBJECT:
CALIFORNIA EMISSIONS RECALL/1990-1991 MODELS - D632
Range Rover of North America, Inc., is conducting a voluntary action to recall 1990 MY and certain 1991 MY Range Rover vehicles registered in the state of California, for the purpose of checking (and adjusting, if necessary) base idle settings and the updating of diagnostic software in the ECU's of all these vehicles. This action will minimize instances of "Check Engine" illumination not related to actual faults in the vehicle's fuel injection system.
The updated ECU software addresses the following:
- Codes 12, 14, 17, 18, 19, 21, 48, 68 or 69 displayed and no fault found with System
- A/C malfunction/cut-off at 65 mph.
NOTE:
THIS RECALL INCORPORATES THE H620 "A/C FIX" PROGRAM.
The improved base idle setting and ECU software is "on-line" at the Factory.
OWNER NOTIFICATION
Owners of vehicles registered in California will be instructed by mail to make an appointment to have their vehicle modified. Arrangements to correct these vehicles should be given high priority at your dealership. A copy of the customer letter and a listing of all customers receiving the mailing is included with this bulletin. Customer letters will be mailed in early March, 1991.
PREVIOUSLY REPAIRED VEHICLES
The attached instructions include VIN ranges for applicable vehicles. However, some vehicles have already been updated prior to delivery or through a special customer satisfaction action via our Technical Hotline or as part of an inventory upgrade completed earlier this month. These vehicles would not exhibit symptoms described in this bulletin and owners of these units will not receive recall notification. Previously repaired vehicles can be identified by:
1. A white tag on the ECU harness, or
2. A label indicating tune # 2419, or
3. The part number PRC9060 (or PRC9060N)
ACTION
1. Replace the ECU or PROM in the existing ECU. See page 3 for ECU Identification. See pages 4 through 7 for work procedure.
2. Install serial link lead (if not present). See page 8.
3. Perform electrical/mechanical pre-checks. Check/adjust base idle using the Hand Held Tester and Base Idle Memory card. See pages 9 through 11. APPLIES ONLY TO SOLD/IN-USE VEHICLES WITH MORE THAN 1000 MILES.
Included with this Service Bulletin is the following package.
1. ECU exchange instructions
2. PROM exchange instructions
3. ECU identification chart
4. Serial link lead instructions
5. Base idle checking/setting work procedure, including electrical/mechanical pre-checklist
6. Warranty information
7. Parts supply information
8. Base idle speed setting memory card for Hand Held Tester
9. "Green dot" I.D. stickers
10. Recall stickers
No ECU is included. Please use the unit you received at the beginning of the H620 A/C Fix Action in August, 1990, as your "float". Remember that this "float" unit was provided at no charge and will ultimately be returned to RRNA. See E-Mail 19-91/01 if this or your other in-stock ECUs have not yet been upgraded to the latest specification. See your Zone Manager if additional "float" ECUs are required.
ECU IDENTIFICATION
ECU's with Soldered In (Non-Replaceable) Prom:
^ Part No. - Factory Installed: PRC7081
PRC8747
^ From VIN ...LA426808 to VIN ...MA483126
^ Date Code on ECU Label: 0590 to 4590
Example: Date Code 2590 = soldered in PROM
ECU's with Socketed (Replaceable) Prom:
^ Part No. - Factory Installed: PRC7081
PRC8747
^ From VIN...LA391190 to VIN...LA426807
^ Date Code (PRC7081): 0490 or below
Example: Date Code - 1289 = socketed PROM
^ Date Code Suffix Letter S (PRC8747): S indicates a socketed PROM on late VIN vehicles.
ECU EXCHANGE INSTRUCTIONS
VINS: ...LA426808 - ...MA483126
1. Remove seat base trim panels and ECU hold down screws.
2. Check multiple connector pins for condition/fit and connect replacement ECU - PRC9060 or PRC9060R. Ignition must be off.
3. Start vehicle - observe that the "Check Engine" light goes out.
4. If O.K., place ECU in clip and secure to floor. CAUTION: The CLIP IS SHARP - EXERCISE CARE.
5. Replace trim panels.
6. Attach and complete both the buff colored tag shipped with new ECU and the normal yellow warranty tag to the removed unit before returning to Lucas.
7. After cleaning the surface, complete and affix a Service Campaign label to the vertical surface of the radiator support panel next to the green Emissions Label. Spray the label with a dear acrylic coating (such as krylon 1301) for weather durability.
NOTE:
Many 1990 model year vehicles are equipped with an external tune resistor located next to the ECU and connected with a blue 2-pin plug to the EFI harness. The updated ECU - PRC9060 contains an internal tune resistor. Remove and discard the existing resistor if equipped.
PROM EXCHANGE INSTRUCTIONS
VINS: ...LA391190 - ...LA426807
Tools Required:
Before removing the ECU, do the following to check for normal operation of the ECU and related systems:
1. Switch on ignition and listen for the one (1) second fuel pump run.
2. Listen for ABS pump operation.
3. Switch off ignition.
WORK PROCEDURE
1. Remove the ECU from under the right front seat and disconnect multiple connector.
2. Place ECU on grounded anti-static mat, slip on anti-static wrist cuff and connect spiral jumper lead to mat. (Use longer jumper wire to ground mat to an electrical conduit or a cold water pipe).
3. Remove 4 TX20 torx screws from ECU and remove bottom half of cover.
4. Remove the printed circuit board from the case and place on anti-static mat.
5. Locate black PROM cover and remove by grasping with pliers across its width at one end or the other (avoid the center). A rocking motion aids removal. Set cover aside for later use.
6. Using the PROM removal tool, carefully lift the PROM from its socket. USE CARE NOT TO DAMAGE THE PRINTED CIRCUIT BOARD OR OTHER COMPONENTS. Store PROM in parts retention area with a completed Warranty Parts Tag.
7. Remove the new PROM (PRM2419) from its package and insert into the socket. NOTE: The half moon cut-out on the PROM faces away from the multiple connector and should align with a similar cut-out on the socket Make sure all pins are engaged before pressing PROM fully in socket. (See illustration).
8. Snap PROM cover in place. If it doesn't fit, re-check PROM for correct installation.
9. Place Printed Circuit Board in case and reassemble cover. Make sure gasket is in place.
10. Attach the multiple connector to the ECU and perform the following initial checks:
A. Switch on ignition - the fuel pump should run for one (1) second. Listen for any unusual noises such as injectors operating or relays clicking which would indicate a problem.
B. Observe that the check engine light comes on and then extinguishes during the bulb check. If not, recheck the multiple connection and, if necessary, replace the ECU.
C. If the vehicle fails 'A' or 'B', re-check the multiple connector pins and socket. If this does not solve the problem, call the Technical Hotline at 1-800-562-5824.
QUALITY CHECK PROCEDURE
Start engine and observe the following:
1. The "Check Engine" light remains out.
2. Idle speed smoothness once stabilized.
3. Switch on the A/C and note idle speed compensation.
4. Rev the engine - no misfire should be noted.
5. Select drive and note idle speed compensation (brakes applied).
Replace the ECU if the vehicle fails any part of the above procedure.
Otherwise:
6. Attach new label
7. Attach "Green dot" sticker
8. Install ECU and seat base trim panels.
9. After cleaning the surface, complete and affix a Service Campaign label to the vertical surface of the radiator support panel next to the green Emissions Label. Spray the label with a dear acrylic coating (such as Krylon 1301) for weather durability.
SERIAL LINK GROUNDING
Work Procedure
1990 Model Year
Up to VIN ...LA441247 If Not Done Previously
1. Locate the diagnostic socket (white) under the rear of the passenger front seat.
2. Locate the black/green wire (BG) on cap side of socket and cut the wire 2" from the socket Strip 1/2" of insulation from the cut ends.
3. Slide the heat shrink tubing (supplied) over the 2" piece of wire from step 2. Join and solder the black connector lead (supplied) to the 2 BG wires. Shrink the insulating tubing over the joint with a heat gun.
4. Remove the orange lock bar and insert the female terminal on the black wire lead into the cap in the lower right hand position (viewed from the rear). Replace the lock bar and snap the cap onto the socket
Parts
1 each - Serial Link Modification Kit - Part No. RTC7670
CHECKING/SETTING BASE IDLE
VEHICLES WITH MORE THAN 1,000 MILES ONLY
Please read the attached Idle Speed Control information before proceeding.
Tools Required:
Range Rover Hand Held Tester (HHT)
Base Idle Memory Card P.N.: ENP1889 (Version 1.0)
Timing Light
Smooth Jaw Hose Clamping Pliers or Equivalent Tool
3/16" Allen Wrench
Parts Required:
Tamperproof Plug P.N.: ETC6874
WORK PROCEDURE
Pre-checks:
1. Updated ECU (PRC9060) or 2419 PROM installed in existing ECU.
2. Serial Link Lead (RTC7670) installed.
3. visually check the following for fit/condition, repair as required.
A. All underhood vacuum hoses.
B. Air flow meter to plenum hose.
C. Throttle housing to stepper motor housing hose.
D. PCV hoses, filter and dipstick seal.
E. Stepper motor plug pins.
F. Any ignition faults
4. Check/clean PCV orifice in "T" piece. Check condition of ground leads/connections, especially at the rear of the left hand cylinder head. Tighten/clean/repair as required.
5. Check/set ignition timing at idle - Spec: 6° BTDC +/- 1.°
CHECKING/SETTING PROCEDURE
1. Connect HHT with Base Idle Memory Card to serial link lead.
2. Start engine.
3. Prompt HHT until stepper motor display is shown on screen.
A. The engine must be warm and in Park or Neutral for the display to occur.
B. Disregard reference to Part No. PRC7081 shown on screen.
C. "F.S. Heater" = Heated windshield.
4. Test drive the vehicle for 1 to 2 miles to stabilize temperature - VERY IMPORTANT.
5. Immediately after the test drive, shut off the engine and wait until the main relay under the passenger seat "clicks" off. Switch off all accessories. The HHT display will indicate "Serial Link Failed" at this point. Disregard, since it will disappear on the next power up.
6. Restart the vehicle, hold the speed to 2,000 RPM for 30 seconds, then allow the engine to idle in Park.
7. Read the HHT display at idle. Spec. is 160 +/- 5 steps. If the position is in range, go to step 9. If it is out of range, go to step 8.
8. Remove the tamperproof plug and, with a 3/16" allen wrench, adjust the bypass screw. Opening (CCW) will increase the position number and vice versa. Shut off engine.
9. Repeat Steps 5, 6 and 7 as a check.
10. Steps 4-8 MUST be completed within a maximum of 10 minutes to ensure an accurate setting. If more than 10 minutes has elapsed, repeat Steps 3-8.
11. With the engine idling, clamp off the hose connecting the throttle housing to the stepper housing such that no air can flow through the hose. Note engine speed. If a stall occurs, repeat the procedure including the pre-checks. If the speed decreases slightly (to less than 600 RPM) proceed to Step 12.
12. Switch off the engine, allow the main relay to "click" off, remove the clamp and restart. Hold the engine at 2000 RPM for 30 seconds, then allow it to idle. Compare the stepper position with that previously checked/set. Repeat setting procedure if a change of greater than 10 steps is noted.
13. After removing HHT serial link harness, re-connect cap on serial link plug.
14. Install new Tamperproof Plug (if removed).
IDLE SPEED CONTROL - SYSTEM OPERATION
The Range Rover EFI System utilizes an idle speed motor (stepper motor) for automatic idle control. Acting on instructions from the ECU, the stepper motor rotates open or closed to compensate idle speed for:
Engine temperature
Engine condition
Altitude
A/C compressor load
Heated windshield load
Automatic transmission load
PCV system vacuum bleed
Alternator loading
Power steering load
From fully open to fully closed, the stepper motor's operation is divided into 180 positions or steps: 0 steps = fully open or retracted, 180 steps = fully closed or extended.
The normal warm engine position depends upon engine condition, base idle setting, throttle position, lack of vacuum leaks, ignition timing and PCV system condition. As accessories are switched on and off, the stepper responds by opening and closing to compensate.
Turning the base idle screw opens or closes a small bypass passage in the plenum and alters the step position. With the engine at full operating temperature, timing correct, no accessory load, the transmission in park or neutral and purge not occurring, the correct setting position is 160 +/- 5 steps. Over time, this value will change slightly as engine conditions change but the system is flexible enough to compensate - provided the initial setting is correct.
When the ignition is switched off (power down) the ECU automatically drives the stepper to the fully open, or 0, position. When the engine is re-started, the stepper closes (adds steps) in response to the ECU's need to maintain correct idle speed regardless of temperature, load, etc. In addition, the air conditioning, heated windshield and automatic transmission provide direct input to the ECU and program in a step change to compensate idle speed slightly. The automatic idle system operates only with the vehicle stopped or below 3 mph with the throttle fully dosed, as indicated by an input from the road-speed transducer. Above 3 mph, the stepper motor is moved to a set position to prevent compensation while driving.
The on-board diagnostics in the ECU constantly compares step position to actual idle speed. If the ECU determines that the stepper is at either 0 or 180 and the idle speed is not within its control limits, the "check engine" light illuminates and a Code 48 is stored.
"CHECK ENGINE" LIGHT RECALL - CLAIM INFORMATION
"CHECK ENGINE" LIGHT RECALL - PARTS SUPPLY PROCESS
March, 1991
Dear California Range Rover Owner:
Range Rover of North America, Inc. is conducting an emissions recall under California Air Resources Board regulations for certain Range Rover vehicles. This is to ensure continued compliance with California air pollution regulations and the best performance for your vehicle. Your vehicle is among the vehicles to which this recall applies.
The inspection and adjustment to your vehicle under this recall will be done at Range Rover's expense. Please contact your Range Rover dealer at your earliest possible convenience to arrange an appointment to have this work performed on your vehicle.
The repair to your vehicle under this recall will involve the checking of the idle speed control system of your Range Rover, with an adjustment if necessary. The repair will also include the updating of the Electronic Control Unit for the fuel injection system. All together, these repairs will provide the best assurance that the "CHECK ENGINE" (Malfunction Indicator Light) will not illuminate inappropriately.
A card (addressed to Range Rover with postage paid), is enclosed with this notice. If you no longer own your vehicle, or if it cannot be reached for a reason such as if it was exported, please provide full information on these circumstances on this card and return this card to Range Rover.
In order to ensure your full protection under the emission warranty provisions, it is recommended that you have your Range Rover serviced as soon as possible.
If you require further information about this recall or if you experience any difficulty in having recall repairs performed, please contact the Range Rover Customer Representative, telephone (800) 637-6837.
Product Support Group