I would use the tool for aligning it but the code stayed with a different engine. Has the synchronizer ever been removed on either of them before it threw a code? Look at the ecm grounds also.
Need help with Camshaft sensor error P0340
- Thread starter Rolltide6019
- Start date
When I purchased the truck the code was there. I put a new synchronizer and sensor on it but still got the error. While all that was going on, my son was driving the truck to work and one day spun a rod bearing. We purchased a NAPA rebuilt engine from a family who had intended to put it in an 98 Ford Explorer but the owner passed away before it ran. I left the synchronizer that was on it but put my new sensor on since I needed a 3-pin and it was brand new from the other engine. So we have an engine and synchronizer that's new to this truck. Plus I purchased a new ECM for it. Its possible that someone put the synchronizer in wrong. I put the one in on the old engine so I know it was correct.
Even with the new one in the old engine it had the code correct? Check it, may be it was installed incorrectly. Even though you have a pulse at pin 58 do you have full 12v at the connector and a good ground? Did you back probe it?
Old engine - new synchronizer and sensor but original ECM. Still had the code although I had a 13v signal into pin 85.
New engine - synchronizer was already on the engine, my new sensor, new ECM, new Crank sensor. Still have the code although I had a 13v signal into pin 85.
I checked the wiring this past Saturday to make sure all were ok. I did NOT check to see if I had 12v at the sensor b/c its pretty hard to get to and with 13v pulses on the signal wire, I had assumed it had to be getting power. Does that sound right to you?
New engine - synchronizer was already on the engine, my new sensor, new ECM, new Crank sensor. Still have the code although I had a 13v signal into pin 85.
I checked the wiring this past Saturday to make sure all were ok. I did NOT check to see if I had 12v at the sensor b/c its pretty hard to get to and with 13v pulses on the signal wire, I had assumed it had to be getting power. Does that sound right to you?
Just for laughs unplug the sensor connector and see what the volts are at 85.
Good idea - I'm gonna do that this afternoon. If I see pulses, I'm gonna shoot myself after I put dynamite under the truck
I know how you feel. I chased a problem down that the dealer had burned through over a grand chasing and had no luck.
After a week on and off I finally found it.
After a week on and off I finally found it.
This is what Ford says in the 1998 OBD II Summary:
https://www.motorcraftservice.com/freeresources/obd
Quote:
Ignition
Distributor Ignition systems (TFI) are no longer in production. Electronic Ignition systems (Electronic Distributorless
Ignition System - EDIS or Coil on Plug - COP) systems are being used on all applications.
The EDIS system uses a chip to process the 36 (or 40) tooth crankshaft position signal, generate a low data rate
PIP signal for the PCM microprocessor and control a 4 or 6 terminal coil pack which fires a pair of spark plugs. One
of these sparkplugs is on the compression stroke, while the other is on the exhaust stroke. The EDIS chip can be
incorporated within the PCM or in a separate ignition control module.
The COP system also uses an EDIS chip in the same way as described above, however, each sparkplug has it’s
own coil which is fired only once on the compression stroke.
The ignition system is checked by monitoring three ignition signals during normal vehicle operation:
Profile Ignition Pickup (CKP, commonly known as PIP), the timing reference signal derived from the
crankshaft 36-tooth wheel and processed by the EDIS chip. PIP is a 50% duty cycle, square wave signal
that has a rising edge at 10 deg BTDC.
Camshaft IDentification (CMP, commonly known at CID), a signal derived from the camshaft to identify the
#1 cylinder
Ignition Diagnostic Monitor (IDM), a signal that indicates that the primary side of the coil has fired. This
signal is received as a digital pulse width signal from the EDIS chip. The EDIS chip determines if the
current flow to the ignition coil reaches the required current (typically 5.5 Amps for COP, 3.0 to 4.0 Amps
for DIS) within a specified time period (typically > 200 microseconds for both COP and DIS). The EDIS
chip also outputs status information when the engine is not running.
First, the relationship between successive PIP events is evaluated to determine whether the PIP signal is rational.
Too large a change in 3 successive PIP indicates a missing or noisy PIP signal (P0320). Next, the CMP edge
count is compared to the PIP edge count. If the proper ratio of CMP events to PIP events is not being maintained
(for example, 1 CMP edge for every 8 PIP edges for an 8-cylinder engine), it indicates a missing or noisy CMP
signal (P0340). Finally, the relationship between IDM edges and PIP edges is evaluated. If there is not an IDM
edge (coil firing) for every PIP edge (commanded spark event), the PCM will look for a pattern of failed IDM events
to determine which ignition coil has failed. If the ignition coil cannot be identified or if the engine is running and
there are no IDM edges, the IDM circuit is malfunctioning (P1351).
Might want to use a dual-trace oscilloscope to verify both the crankshaft and camshaft signals and their relationship to each other, to make sure that the proper ratio of CMP to PIP events is being maintained.
https://www.motorcraftservice.com/freeresources/obd
Quote:
Ignition
Distributor Ignition systems (TFI) are no longer in production. Electronic Ignition systems (Electronic Distributorless
Ignition System - EDIS or Coil on Plug - COP) systems are being used on all applications.
The EDIS system uses a chip to process the 36 (or 40) tooth crankshaft position signal, generate a low data rate
PIP signal for the PCM microprocessor and control a 4 or 6 terminal coil pack which fires a pair of spark plugs. One
of these sparkplugs is on the compression stroke, while the other is on the exhaust stroke. The EDIS chip can be
incorporated within the PCM or in a separate ignition control module.
The COP system also uses an EDIS chip in the same way as described above, however, each sparkplug has it’s
own coil which is fired only once on the compression stroke.
The ignition system is checked by monitoring three ignition signals during normal vehicle operation:
Profile Ignition Pickup (CKP, commonly known as PIP), the timing reference signal derived from the
crankshaft 36-tooth wheel and processed by the EDIS chip. PIP is a 50% duty cycle, square wave signal
that has a rising edge at 10 deg BTDC.
Camshaft IDentification (CMP, commonly known at CID), a signal derived from the camshaft to identify the
#1 cylinder
Ignition Diagnostic Monitor (IDM), a signal that indicates that the primary side of the coil has fired. This
signal is received as a digital pulse width signal from the EDIS chip. The EDIS chip determines if the
current flow to the ignition coil reaches the required current (typically 5.5 Amps for COP, 3.0 to 4.0 Amps
for DIS) within a specified time period (typically > 200 microseconds for both COP and DIS). The EDIS
chip also outputs status information when the engine is not running.
First, the relationship between successive PIP events is evaluated to determine whether the PIP signal is rational.
Too large a change in 3 successive PIP indicates a missing or noisy PIP signal (P0320). Next, the CMP edge
count is compared to the PIP edge count. If the proper ratio of CMP events to PIP events is not being maintained
(for example, 1 CMP edge for every 8 PIP edges for an 8-cylinder engine), it indicates a missing or noisy CMP
signal (P0340). Finally, the relationship between IDM edges and PIP edges is evaluated. If there is not an IDM
edge (coil firing) for every PIP edge (commanded spark event), the PCM will look for a pattern of failed IDM events
to determine which ignition coil has failed. If the ignition coil cannot be identified or if the engine is running and
there are no IDM edges, the IDM circuit is malfunctioning (P1351).
Might want to use a dual-trace oscilloscope to verify both the crankshaft and camshaft signals and their relationship to each other, to make sure that the proper ratio of CMP to PIP events is being maintained.
Last edited:
Here is the Ford test for P0340
1998 PCED OBDII-A SECTION 5A: Pinpoint Tests
--------------------------------------------------------------------------------
DR: Camshaft Position (CMP) Sensor DR: Introduction
--------------------------------------------------------------------------------
DR1 DTC P0340: CHECK IF ENGINE WILL START
Note: Diagnostic Trouble Code (DTC) P0340 indicates that Self-Test has detected a Camshaft Position (CMP) Sensor circuit failure.
Note: Refer to the Pinpoint Test Schemaic to determine the type of CMP sensor.
Possible causes:
CMP circuit open.
CMP circuit shorted to GND.
CMP circuit shorted to PWR.
SIG RTN or CMP/TSS GND open (VR type).
VPWR open (Hall effect type).
CMP Sensor (Hall effect type) not installed correctly.
Damaged CMP Sensor.
Damaged PCM.
Start engine.
Will the engine start?
Yes No
GO to DR2 . DTC P0340 is not the cause of the No Start. GO to Section 3A to diagnose the No Start symptom.
DR2 CLEAR AND ATTEMPT TO RE-GENERATE DTC P0340
Complete PCM Reset to clear DTCs.
Start engine.
Increase rpm to greater than 1500 rpm for 10 seconds. Repeat two times.
Key off.
Retrieve all Continuous Memory DTCs.
Is DTC P0340 present?
Yes No
For VR type CMP:
GO to DR5
For Hall Effect type CMP:
GO to DR3 The fault that produced DTC P0340 is intermittent. GO to Pinpoint Test Step Z1 with the following data: List of Possible causes.
DR3 CHECK VPWR VOLTAGE TO CMP SENSOR
Disconnect CMP sensor.
Key on, engine off.
Measure VPWR circuit voltage at the CMP sensor harness connector.
Key off.
Was voltage greater than 10.5 volts?
Yes No
GO to DR4 . REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .
DR4 CHECK PWR GND TO CMP SENSOR
Measure resistance of PWR GND circuit between CMP sensor harness connector and battery negative post.
Is resistance less than 5.0 ohms?
Yes No
GO to DR5 . REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .
DR5 CHECK FOR OPEN CMP AND SIG RTN CIRCUITS BETWEEN PCM AND CMP SENSOR
Install breakout box, leave PCM disconnected.
Measure resistance of CMP circuit between PCM test pin 85 and CMP sensor harness connector.
For VR type CMP (Contour/Mystique, Escort/Tracer) :
Measure resistance of CMP/TSS GND circuit between PCM test pin 76 and CMP sensor harness connector.
For VR type CMP: (All others
Measure resistance of SIG RTN circuit between PCM test pin 91 and CMP sensor harness connector.
Are resistance measurements less than 5.0 ohms?
Yes No
GO to DR6 . REPAIR open circuit. RESTORE vehicle. RERUN Quick Test .
DR6 CHECK CMP CIRCUIT FOR SHORT TO POWER IN HARNESS
CMP sensor disconnected.
Key on, engine off.
Measure voltage between PCM test pin 85 and PCM test pins 51 and 103.
Key off.
Was voltage less than 1.0 volt?
Yes No
GO to DR7 . REPAIR short circuit. RESTORE vehicle. RERUN Quick Test .
DR7 CHECK CMP CIRCUIT FOR SHORT TO GND AND SIG RTN IN HARNESS
CMP sensor disconnected.
Disconnect scan tool from DLC.
Measure resistance between PCM test pin 85 and PCM test pins 51, 91 and 103.
Was each resistance greater than 10,000 ohms?
Yes No
GO to DR8 . REPAIR short circuit. RESTORE vehicle. RERUN Quick Test .
DR8 CHECK FOR SHORTS IN PCM
Reconnect PCM to breakout box.
Measure resistance between PCM test pin 85 and PCM test pins 23, 51, 71, 91, 97 and 103.
Is each resistance greater than 500 ohms?
Yes No
For VR type CMP:
GO to DR9 .
For Hall Effect type CMP:
GO to DR10 . REPLACE PCM. RESTORE vehicle. RERUN Quick Test .
DR9 CHECK CMP SENSOR OUTPUT
Reconnect CMP sensor.
Digital multimeter on ac scale (to monitor less than 5.0 volts).
Measure voltage between PCM test pins 85 and 51 while running engine at varying rpm.
Does ac voltage vary greater than 0.1 volt ac?
Yes No
REPLACE PCM. RESTORE vehicle. RERUN Quick Test . REPLACE CMP sensor. RESTORE vehicle. RERUN Quick Test .
DR10 CHECK CMP SENSOR OUTPUT
Disconnect PCM.
Reconnect CMP sensor.
Connect digital multimeter between PCM test pins 85 and 51.
Bump engine in short bursts with the starter without starting engine for at least 10 engine revolutions.
Does voltage reading switch between low (less than 2.0 volts dc) and high (greater than 8.0 volts dc)?
Yes No
A Hall effect type CMP sensor that is installed out of synchronization will product a DTC. VERIFY the correct installation by refering to the Powertrain/Engine Group in the Workshop Manual. If CMP is installed properly, REPLACE PCM. RESTORE vehicle. RERUN Quick Test . REPLACE CMP sensor. RESTORE vehicle. RERUN Quick Test .
--------------------------------------------------------------------------------
1998 PCED OBDII-A SECTION 5A: Pinpoint Tests
--------------------------------------------------------------------------------
DR: Camshaft Position (CMP) Sensor DR: Introduction
--------------------------------------------------------------------------------
DR1 DTC P0340: CHECK IF ENGINE WILL START
Note: Diagnostic Trouble Code (DTC) P0340 indicates that Self-Test has detected a Camshaft Position (CMP) Sensor circuit failure.
Note: Refer to the Pinpoint Test Schemaic to determine the type of CMP sensor.
Possible causes:
CMP circuit open.
CMP circuit shorted to GND.
CMP circuit shorted to PWR.
SIG RTN or CMP/TSS GND open (VR type).
VPWR open (Hall effect type).
CMP Sensor (Hall effect type) not installed correctly.
Damaged CMP Sensor.
Damaged PCM.
Start engine.
Will the engine start?
Yes No
GO to DR2 . DTC P0340 is not the cause of the No Start. GO to Section 3A to diagnose the No Start symptom.
DR2 CLEAR AND ATTEMPT TO RE-GENERATE DTC P0340
Complete PCM Reset to clear DTCs.
Start engine.
Increase rpm to greater than 1500 rpm for 10 seconds. Repeat two times.
Key off.
Retrieve all Continuous Memory DTCs.
Is DTC P0340 present?
Yes No
For VR type CMP:
GO to DR5
For Hall Effect type CMP:
GO to DR3 The fault that produced DTC P0340 is intermittent. GO to Pinpoint Test Step Z1 with the following data: List of Possible causes.
DR3 CHECK VPWR VOLTAGE TO CMP SENSOR
Disconnect CMP sensor.
Key on, engine off.
Measure VPWR circuit voltage at the CMP sensor harness connector.
Key off.
Was voltage greater than 10.5 volts?
Yes No
GO to DR4 . REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .
DR4 CHECK PWR GND TO CMP SENSOR
Measure resistance of PWR GND circuit between CMP sensor harness connector and battery negative post.
Is resistance less than 5.0 ohms?
Yes No
GO to DR5 . REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test .
DR5 CHECK FOR OPEN CMP AND SIG RTN CIRCUITS BETWEEN PCM AND CMP SENSOR
Install breakout box, leave PCM disconnected.
Measure resistance of CMP circuit between PCM test pin 85 and CMP sensor harness connector.
For VR type CMP (Contour/Mystique, Escort/Tracer) :
Measure resistance of CMP/TSS GND circuit between PCM test pin 76 and CMP sensor harness connector.
For VR type CMP: (All others
Measure resistance of SIG RTN circuit between PCM test pin 91 and CMP sensor harness connector.
Are resistance measurements less than 5.0 ohms?
Yes No
GO to DR6 . REPAIR open circuit. RESTORE vehicle. RERUN Quick Test .
DR6 CHECK CMP CIRCUIT FOR SHORT TO POWER IN HARNESS
CMP sensor disconnected.
Key on, engine off.
Measure voltage between PCM test pin 85 and PCM test pins 51 and 103.
Key off.
Was voltage less than 1.0 volt?
Yes No
GO to DR7 . REPAIR short circuit. RESTORE vehicle. RERUN Quick Test .
DR7 CHECK CMP CIRCUIT FOR SHORT TO GND AND SIG RTN IN HARNESS
CMP sensor disconnected.
Disconnect scan tool from DLC.
Measure resistance between PCM test pin 85 and PCM test pins 51, 91 and 103.
Was each resistance greater than 10,000 ohms?
Yes No
GO to DR8 . REPAIR short circuit. RESTORE vehicle. RERUN Quick Test .
DR8 CHECK FOR SHORTS IN PCM
Reconnect PCM to breakout box.
Measure resistance between PCM test pin 85 and PCM test pins 23, 51, 71, 91, 97 and 103.
Is each resistance greater than 500 ohms?
Yes No
For VR type CMP:
GO to DR9 .
For Hall Effect type CMP:
GO to DR10 . REPLACE PCM. RESTORE vehicle. RERUN Quick Test .
DR9 CHECK CMP SENSOR OUTPUT
Reconnect CMP sensor.
Digital multimeter on ac scale (to monitor less than 5.0 volts).
Measure voltage between PCM test pins 85 and 51 while running engine at varying rpm.
Does ac voltage vary greater than 0.1 volt ac?
Yes No
REPLACE PCM. RESTORE vehicle. RERUN Quick Test . REPLACE CMP sensor. RESTORE vehicle. RERUN Quick Test .
DR10 CHECK CMP SENSOR OUTPUT
Disconnect PCM.
Reconnect CMP sensor.
Connect digital multimeter between PCM test pins 85 and 51.
Bump engine in short bursts with the starter without starting engine for at least 10 engine revolutions.
Does voltage reading switch between low (less than 2.0 volts dc) and high (greater than 8.0 volts dc)?
Yes No
A Hall effect type CMP sensor that is installed out of synchronization will product a DTC. VERIFY the correct installation by refering to the Powertrain/Engine Group in the Workshop Manual. If CMP is installed properly, REPLACE PCM. RESTORE vehicle. RERUN Quick Test . REPLACE CMP sensor. RESTORE vehicle. RERUN Quick Test .
--------------------------------------------------------------------------------
Sorry to bump an old thread but I'm wondering if you ever got this figured out? Having a similar problem on my 3.0. Replaced the camshaft sensor and synchronizer assembly with a brand new one, engine runs smooth, but still getting the P0340 code.
If your scope is at least 2 channels you could compare the cam sensor signal against the crank sensor. I dug up a known good waveform in case you want to go that route. The only other bulletproof way to verify the synchro is timed correctly is unfortunately to get the tool and do it manually.
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